Drug & Alcohol Testing

Drug & Alcohol Testing

Hepatotoxicity may be fatal, but is idiosyncratic and not preventable by routinely monitoring liver enzymes. Hepatotoxicity occurs in very young children, most often those on multiple anticonvulsants.1Valproate-induced cytopenias may be dose-related and warrant monitoring of complete blood counts during therapy.2Encephalopathy with hyperammonemia without liver function test abnormalities may occur.3Pregnant women in first month are at risk for neural tube defects.Valproate is absorbed rapidly and completely following oral administration; peak plasma concentrations usually occur within two hours after ingestion of liquid preparations and three to four hours after ingestion of the delayed-release tablet preparation, divalproex sodium, which contains sodium valproate and valproic acid. Food delays absorption but does not affect bioavailability.The plasma protein binding of valproate is saturable within the usual therapeutic range (approximately 90% at 75 μg/mL). Usual effective plasma concentrations range from 50−120 μg/mL.4With a daily dose of more than 500 mg, plasma concentrations may not increase proportionately because clearance increases with an increase in the free fraction. Daily fluctuations (up to two times higher) in free fraction and clearance also occur as a result of displacement by free fatty acids or circadian influences; thus, when plasma concentrations are being monitored, samples should be taken at a uniform time. Many neurologists recommend measuring trough concentrations.Valproate is eliminated almost exclusively by hepatic metabolism. The metabolic fate is complex. A variety of conjugation and oxidative processes are involved, including entry into pathways (eg, beta oxidation) normally reserved for endogenous fatty acids. As the dose is increased, mitochondrial beta oxidation becomes saturated and increased glucuronidation occurs.Metabolites may contribute to both antiepileptic and hepatotoxic effects. The antiepileptic activity of valproate (including the time course) is poorly correlated with steady-state valproate plasma concentrations. One unsaturated metabolite, 2-n-propyl-4-pentenoic acid (4-ene-VPA), has been proposed as a key hepatotoxic metabolite. The formation of this metabolite is increased by concomitant use of phenytoin, phenobarbital, carbamazepine, and other drugs that induce cytochrome P450. Due to inhibition of the same enzyme system, valproic acid may cause elevated levels of clomipramine with resultant seizures when the two agents are co-administered.5The half-life of valproate in adults is 12 to 16 hours. In epileptic patients receiving polytherapy, the half-life is approximately nine hours, although five hours has also been reported. The half-lives in school-age children and young adolescents are well within the range of values in adults. Elimination half-lives are longer in neonates and generally shorter during middle and late infancy. Although hepatic clearance is reduced, the half-life in geriatric patients is approximately 15 hours. This has been attributed to the larger free fraction observed in this age group, especially in those with hypoalbuminemia.

Drug & Alcohol Testing

As a potent inducer of P450 enzymes CYP3A4, CYP1A2, and CYP2C9, co-administration of phenytoin can decrease plasma concentrations of tricyclic antidepressants and most other antiepileptic drugs.1,2Despite normal levels, phenytoin may interfere with the actions of other drugs, including cyclosporine, oral anticoagulants, oral contraceptives, and theophylline; appropriate laboratory monitoring of some of these agents is advised. The half-life of phenytoin in adults is 20 to 40 hours; in children, it is approximately 10 hours. Teratogenic effects of phenytoin have been proposed but not confirmed; the risks in women of childbearing age should be balanced against the risks of increased seizures.3

Drug & Alcohol Testing

Lithium is completely absorbed six to eight hours after oral administration. Since the onset of action is slow (5 to 10 days), parenteral administration is of no advantage. The plasma half-life is 17 to 36 hours, and this drug is eliminated almost entirely by the kidneys. Lithium clearance averages approximately 20% of creatinine clearance, but significant variability exists among patients.Lithium ion is not protein bound, is distributed in total body water, and is concentrated in various tissues to different degrees. After a steady-state has been achieved, the lithium level in cerebrospinal fluid is about 40% of that in serum, and renal clearance for an individual remains relatively constant.In general, a good correlation exists between the serum concentration of lithium ion and therapeutic efficacy and toxicity; however, some patients who show no therapeutic benefit have adequate serum concentrations of lithium but low erythrocyte concentrations. Since lithium works intracellularly, the erythrocyte concentration of the drug may be more relevant than levels in serum; therefore, in unresponsive patients, doses that produce higher than usual serum concentrations can be used if erythrocyte concentrations are lower.

Drug & Alcohol Testing

Cyclosporine is an immunosuppressive agent derived fromTolypocladium inflatum gams, a fungus originally isolated from a Norwegian soil sample. The agent is used extensively to control rejection of organ transplants, especially of liver, heart, or kidney. The effectiveness of cyclosporine results from specific and reversible inhibition of immunocompetent lymphocytes in the G0 and G1 phase of the cell cycle. T-lymphocytes are preferentially inhibited. The T-helper cell is the main target, although the T-suppressor cell may also be suppressed. Cyclosporine also inhibits lymphokine production and release, including interleukin-2.Monitoring blood levels is imperative because the pharmacokinetics of cyclosporine are not only complex but vary over time in the same patient; thus, blood levels cannot be well predicted from dosing schedules. Furthermore, this drug has a narrow therapeutic window and significant toxicity at levels above that range.Renal toxicitywith eventual renal failure is the most severe complication. Other assays to assess renal function (ie, BUN, creatinine clearance) should be ordered along with cyclosporine level, since toxicity may begin even with “acceptable” blood levels. Other toxicities include hypertension, convulsions, tremors, pulmonary edema, and an increased risk of lymphoma.Drugs that enhance the potential toxicity of cyclosporine, include aminoglycoside antibiotics, amphotericin B, acyclovir, ketoconazole, lovastatin, NSAIDs, and ranitidine. Agents that are CYP3A3 and CYP3A4 inhibitors raise cyclosporine levels by decreasing biotransformation. These include methylprednisolone, amphotericin B, cimetidine, amiodarone, fluoxetine, protease inhibitors, erythromycin, and grapefruit juice. Agents that increase hepatic metabolism and, thus, lower cyclosporine levels include phenobarbital, phenytoin, carbamazepine, rifampin, trimethoprim, and St John's wort.Because results vary depending on the method and cyclosporine antibody employed (monospecific or polyspecific), it is best for a given patient's specimens to be analyzed at a single laboratory to eliminate as many assay-dependent variables as possible.Half-life of elimination; Oral: May be prolonged in patients with hepatitis impairment and may be shorter in pediatric patients due to the higher metabolism rate. The elimination profile of cyclosporine is biphasic. An early elimination phase with an apparent half-life that typically ranges from three to seven hours is followed by a slower elimination of phase with an apparent half-life ranging from 18 to 25 hours. The peak concentration is reached in four to six hours.

Drug & Alcohol Testing

Lithium is used to treat manic-depressive disorders and the manic phase of affective disorders, including mania. The therapeutic window is relatively small. Therapeutic drug monitoring is useful to optimize dose and avoid toxicity.

Drug & Alcohol Testing

Ethanol is absorbed rapidly from the GI tract. Peak blood levels usually occur within 40 to 70 minutes on an empty stomach. Food in the stomach can decrease the absorption of alcohol. Ethanol is metabolized by the liver to acetaldehyde. Once peak blood ethanol levels are reached, disappearance is linear; a 70 kg man metabolizes 7−10 g of alcohol/hour (15±5 mg/dL/hour). The urine:blood ratio is considered to be about 1.35:1 but is quite variable. The average saliva:blood ratio is 1:20. Symptoms of intoxication in the presence of low alcohol levels could indicate a serious acute medical problem requiring immediate attention. The half-lives and effectiveness of certain drugs (eg, barbiturates, etc) are increased in the presence of ethanol.

Drug & Alcohol Testing

Offered as part of multiple lab tests

Drug & Alcohol Testing

Ethyl glucuronide and ethyl sulfate are metabolites of ethanol (alcohol) that may be present in urine after ingestion of, or exposure to, drinks, foods, medication or other products containing ethyl alcohol. Incidental exposure to alcohol-containing products such as mouthwash or hand sanitizer have also been shown to produce positive alcohol metabolites test results. LC-MS/MS testing detects EtG and EtS regardless of the source. Therefore, we encourage you to interpret alcohol metabolite test results in light of the clinical picture.

Drug & Alcohol Testing

This assay is used for the detection of nicotine and cotinine in urine to determine the tobacco exposure status of the individual. Nicotine has a short half-life of approximately forty minutes; its presence may indicate recent tobacco exposure. Cotinine, the major nicotine metabolite, has a half-life of 24 hours and is detectable for several days after cessation of tobacco exposure.

Drug & Alcohol Testing, Mental Health & Neurological

Amitriptyline is a tricyclic antidepressant that blocks the reuptake of serotonin at nerve endings and possesses high anticholinergic activity and cardiovascular toxicity. The drug is extensively metabolized to many polar compounds, the chief of which is nortriptyline. It is also an antidepressant. Both drugs are prescribed for depression and a range of other disorders.Amitriptyline has a peak serum concentration two to six hours postoral dose, and steady-state is achieved after three to eight days of chronic oral dosing. The half-life is 17 to 40 hours and the usual therapeutic range (predose sample at steady-state) includes nortriptyline and is 80−200 ng/mL. Nortriptyline is administered orally, has a half-life of 15 to 90 hours, and peak serum values two to six hours postoral dose. Steady-state is achieved after 4 to 20 days of chronic dosing. Therapeutic levels of nortriptyline alone are 50−150 ng/mL.All the tricyclic antidepressants have significantdrug interactions. Being potent inducers of hepatic drug-metabolizing enzymes, particularly CYP3A4, CYP1A2, and CYP2C9, the antiepileptic drugs, carbamazepine, phenytoin, phenobarbital, and primidone stimulate the oxidative transformation of concurrently prescribed antidepressants.1This results in decreased drug levels of the antidepressant. To a lesser extent, co-administration of oxcarbazepine, topiramate, and felbamate can also result in decreased antidepressant levels.Other tricyclic antidepressant drug interactions:hydrocortisone, methylphenidate, and phenothiazines increase tricyclic levels; tricyclics impair the antihypertensive effectiveness of clonidine and guanethidine; tricyclics and alcohol produce additive sedative effects, tricyclics and antiparkinsonism agents have potent anticholinergic side effects, and tricyclics and MAO inhibitors should not be co-administered because of the potential for antihypertensive and CNS crises.Tricyclics should be avoided in pregnant and lactating women because these drugs have not been established as safe. Geriatric patients are especially prone to postural hypotension, urinary retention, and sedation.2In general, it has been reported that, “Therapeutic drug monitoring of antidepressants allows us to take into account the influence of factors such as co-medications, diet, smoking habit, impaired organ function, and compliance. Therapeutic drug monitoring and genotyping are thus complementary, and their combined use contributes to improve pharmacotherapy with antidepressants and other drugs.”3

Drug & Alcohol Testing

Leukopenia may be dose related, and necessitates stopping the drug if the absolute neutrophil count falls to <1000/mm3.3Hyponatremia may occur, especially in older patients. Patients in the first month of pregnancy are at increased risk of neural tube defects. Carbamazepine may interfere with the actions of theophylline, oral contraceptives, oral anticoagulants, or doxycycline. Conversely, there have been reports indicating fluoxetine may mediate an increase in carbamazepine plasma concentrations due to inhibition of CYP3A4.2

Drug & Alcohol Testing

Offered as part of multiple lab tests

Drug & Alcohol Testing

Carbamazepine is an anticonvulsant which is structurally related to the tricyclic antidepressants and is useful in treating patients with temporal lobe epilepsy. Carbamazepine levels are monitored to assure adequate therapeutic levels are achieved and to avoid toxicity.

Drug & Alcohol Testing, Mental Health & Neurological

Topiramate is an anticonvulsant drug used as an adjunctive therapy in the treatment of patients with partial and secondary generalized epilepsy. Topiramate is a sulfamate-substituted monosaccharide, derived from D-fructose. The animal models suggest that topiramate exerts its anticonvulsant effect primarily by blocking the spread of seizures, rather than by elevating the seizure threshold. Pharmacokinetic studies in humans have shown that topiramate is absorbed rapidly, excreted largely unchanged in the urine.1Carbamazepine and phenytoin can significantly induce the metabolism of topiramate, whereas valproic acid has only a slight influence on topiramate concentrations.2The elimination half-life of topiramate is 18 to 23 hours and is dose-dependent; however, children, as differentiated from adults, can require at least a twofold increase in dose to achieve a comparable plasma level.3The drug is approximately 15% protein bound. Although carbamazepine and phenytoin induce the metabolism of topiramate and shorten its half-life, topiramate has no significant effect on the plasma concentrations of these drugs or valproic acid. Maintenance doses of topiramate, given twice daily, range from 300−600 mg/day. Side effects include dizziness, reduced cognitive function, weight loss, and headache. As observed with many therapeutic agents, the interpatient variability in clinical response at similar topiramate plasma concentration can be appreciable. Differences in plasma levels between responders, nonresponders, and seizure-free patients can be indiscernible.

Drug & Alcohol Testing

Phenobarbital has a half-life of 84 to 108 hours. Phenobarbital can affect the metabolism of phenytoin, ethosuximide, and increase the clearance and elimination of chloramphenicol, theophylline, oral anticoagulants (warfarin), cyclosporine, and oral contraceptives; where appropriate, the use of these drugs in patients on phenobarbital should be monitored clinically and through the laboratory.

Drug & Alcohol Testing

Lamotrigine is an antiepileptic drug (AED) of the phenyltriazine class that is chemically unrelated to existing AEDs. The precise mechanism of action is unknown although it has been postulated that lamotrigine inhibits voltage-sensitive sodium channels thereby stabilizing neuronal membranes and consequently modulating presynaptic transmitter release of excitatory amino acids (eg, glutamate, aspartate). Lamotrigine is 55% bound to plasma proteins and is metabolized predominantly to an inactive 2-N-glucuronide conjugate. Peak plasma concentration occurs at 1.4 to 4.8 hours following oral administration.1The elimination half-life varies from 12 to 70 hours. The longer half-lives are observed in patients on concomitant valproic acid therapy. Accordingly, if lamotrigine is coadministered with valproic acid, the dose of lamotrigine must be reduced to less than half the normal dosage. The most common adverse reactions are associated with the use of lamotrigine in combination with other anticonvulsants, and include dizziness, diplopia, ataxia, blurred vision, nausea and vomiting, somnolence, headache, and rash. The anticonvulsants phenytoin, phenobarbital, primidone, and carbamazepine can reduce lamotrigine levels when coadministered.2Conversely, lamotrigine can reduce levels of levetiracetam when coadministered.3In children, investigators4have found large differences in lamotrigine plasma levels in patients with improvement in seizure frequency, but patients who were seizure-free had higher lamotrigine levels than other patients in the study.

Drug & Alcohol Testing

Offered as part of multiple lab tests

Drug & Alcohol Testing

This assay is used for the detection of nicotine and two primary metabolites, 3-OH cotinine and cotinine in serum and plasma to determine the tobacco exposure status of an individual. Nicotine has a short half-life of approximately sixty minutes; Its presence may indicate recent tobacco exposure. The half-life of the primary metabolites is longer and provides a larger window of detection for tobacco exposure. Individuals exposed to passive tobacco smoke (environmental or second-hand) can have detectable concentrations of nicotine and its metabolites depending on the type of exposure. The ranges of concentrations related to passive exposure are not well established but normally are less than those attributed to active tobacco users.

Drug & Alcohol Testing

Cotinine is the major metabolite of nicotine and may be detected for as long as seven days after exposure. Cutoff is set high to rule out passive inhalation.

Drug & Alcohol Testing

Offered as part of multiple lab tests

Drug & Alcohol Testing

The test is a screening assay using a homogeneous enzyme immunoassay method of analysis. Therapeutic urine drug monitoring is important for ensuring compliance to treatment strategies, as well as ensuring non-diversion for illicit purposes. Urine or oral fluid are the specimens of choice for routine monitoring of patients taking prescription drugs. Use of serum/plasma should be limited to anuretic patients, or where a patient's clinical appearance does not coincide with their prescribed medications. No single monitoring approach provides adequate information about the pattern or dose of patient drug use. Safest prescribing habits should include a combination of tools and laboratory test results to correctly detect drug use patterns. Urine drug test results equal to or greater than cutoff are reported as positive and results less than cutoff are reported as negative.

Drug & Alcohol Testing

Offered as part of multiple lab tests

Drug & Alcohol Testing

The test is a screening assay using a homogeneous enzyme immunoassay method of analysis. Therapeutic urine drug monitoring is important for ensuring compliance to treatment strategies, as well as ensuring non-diversion for illicit purposes. Urine or oral fluid are the specimens of choice for routine monitoring of patients taking prescription drugs. Use of serum/plasma should be limited to anuretic patients, or where a patient's clinical appearance does not coincide with their prescribed medications. No single monitoring approach provides adequate information about the pattern or dose of patient drug use. Safest prescribing habits should include a combination of tools and laboratory test results to correctly detect drug use patterns. Urine drug test results equal to or greater than cutoff are reported as positive and results less than cutoff are reported as negative.

Drug & Alcohol Testing, Heart Health & Cardiovascular

Digoxin is a cardiac glycoside derived from the digitalis plant. It is used to treat congestive heart failure and atrial dysrhythmias. Digoxin levels are monitored to assure adequate therapeutic levels are achieved and to avoid toxicity.

Drug & Alcohol Testing

Sirolimus may be administered in conjunction with cyclosporine (CsA) and corticosteroids to reduce or prevent host graft rejection. Using this therapy, peak concentrations are achieved in one to two hours. The mean terminal elimination half-life is 62 hours.1Drug-drug interactions, including CsA, may alter the pharmacokinetics of sirolimus, making therapeutic drug monitoring appropriate.

Drug & Alcohol Testing

Offered as part of multiple lab tests

Drug & Alcohol Testing

Valproic acid is used as an anticonvulsant to treat certain types of seizures, to prevent migraine headaches and to treat various psychiatric illnesses such as bipolar disorder and aggression. Drugs that compete for protein-binding sites with valproic acid can increase the concentration of valproic acid. Therapeutic drug monitoring is useful to optimize dose. Measurement of the free concentration is useful if toxicity is suspected.

Drug & Alcohol Testing

Phenytoin is an anticonvulsant hydantoin used for the treatment of generalized tonic-clonic (grand mal) and complex partial seizures. Phenytoin is also used for prophylaxis in neurosurgical procedures. Phenytoin levels are monitored to assure adequate therapeutic levels are achieved and to avoid toxicity.

Drug & Alcohol Testing

Amiodarone is an antiarrythmic drug. Therapeutic drug monitoring is useful to monitor compliance and avoid toxicity.

Drug & Alcohol Testing

Offered as part of multiple lab tests

Drug & Alcohol Testing, Mental Health & Neurological

Levetiracetam (LTA), a piracetam analogue, is an antiepileptic drug (AED) structurally unrelated to other AEDs. The exact mechanism by which LTA acts has not been determined at this time; however, binding sites for the drug have been identified in synaptic plasma membranes of CNS neurons. Secondary alteration in GABA-related enzymes may result from binding to neurons in specific regions of the CNS.1While approximately one-fourth of LTA is converted by enzymatic hydrolysis to a carboxylic acid metabolite, the drug has no effect on UDP glucuronyltransferase, epoxide hydrolase, or enzymes in the CYP system,1,2resulting in minimal interactions with other AEDs in a polypharmacy regimen. LTA has minimal protein binding (<10%), an elimination half-life of six to eight hours in healthy adults, six hours in children, and 10-11 hours in the elderly. In healthy adults, approximately 95% of LTA and metabolites are excreted in the urine. Renal impairment can, therefore, decrease clearance from 35% to 60%.3,4A single 1000 mg dose or 1000 mg twice daily doses produced peak levels of 31 μg/mL and 43 μg/mL, respectively.3Neuropsychiatric adverse events of aggression, anger, and irritability, as well as adverse reactions of leukopenia, neutropenia, pancytopenia, and thrombocytopenia have been reported.5

Drug & Alcohol Testing

Offered as part of multiple lab tests

Drug & Alcohol Testing

CDT testing can be an effective tool for the early diagnosis of chronic alcohol misuse, for the detection of patients addicted to alcohol, and for the follow-up of treatment and diagnosis of alcohol relapse.CDT quantitation is useful in detecting abusive alcohol consumption (defined as ethanol consumption >40 mL per day for at least two weeks) and a more specific marker for alcohol exposure than other available markers, such as γ-glutamyl transferase (GGT). It enables early detection of alcohol misuses and follow-up of alcoholic patients.On stopping alcohol consumption, the CDT level goes back to normal after two to four weeks. If the patient starts drinking after withdrawal, CDT increases in a few days.Transferrin is an 80-kDa serum glycoprotein produced by the liver. Its function is to carry iron around an organism mediated by iron-binding properties. Transferrin comprises a single polypeptide chain with two polysaccharide chains ended by a sialic acid residue. There are several isoforms of human transferrin with different levels of sialylation. Carbohydrate-deficient transferrin (CDT), defined by 2 sialo and 0 sialo isoforms, is a marker of chronic alcohol abuse.

Drug & Alcohol Testing

Heavy alcohol use (defined as >4 or 5 beverages per day for two weeks or more) is commonly associated with elevated CDT levels as are certain liver diseases such as primary biliary cirrhosis and chronic active hepatitis and in some patients with genetic D variants of transferrin.

Drug & Alcohol Testing

Offered as part of multiple lab tests

Drug & Alcohol Testing

Lamotrigine is an anticonvulsant drug used as adjunctive treatment for refactory partial seizures.

Drug & Alcohol Testing

Theophylline is prescribed for bronchial asthma, for chronic obstructive pulmonary disease, and for newborn apnea. The drug is extensively metabolized1with peak serum levels reached four hours after oral dose. Troleandomycin and erythromycin may slow theophylline elimination. Heart failure, liver disease, prolonged fever, certain infections, and obesity may have similar effects. Prolonged half-life occurs in premature infants.Dosage should be reduced in these situations.By contrast, half-life is shortened in smokers, variable with phenobarbital administration; higher doses are also tolerated in acidemia. Smokers on the average are reported to need 1.5 to 2 times as much of the drug as nonsmokers to achieve the same effects. Optimal resampling time after change in dosage is 48 hours for adults, one to two days for children. The half-life of theophylline is from 3 to 10 hours for adults and 1.4 to 7.9 hours for children, but varies between individuals.Studying serum concentrations and toxic effects, Bertino et al found toxicity with peak theophylline concentrations as low as 19.4 mg/L. Recognizing theophylline toxicity over a wide range of theophylline levels, these authors questioned the association between the severity of toxic effects and serum concentrations.2Aitken and Martin also found lack of correlation between serum theophylline level and toxic effects.3Blood levels should be interpreted in light of the patient's clinical status and use of other medications.Toxic effectsinclude nausea, vomiting, diarrhea, headache, atrial and ventricular arrhythmias, tremors, and convulsions.

Drug & Alcohol Testing

Ethylglucuronide (EtG) and Ethylsulfate (EtS) are metabolites of ethanol. While EtG has been used as a long-term biomarker in urine testing for more than 7 years, EtS has more recently been incorporated into testing programs. Scientific literature indicates that EtG may be detectable for up to 80 hours and that EtS may be detectable for 24 hours or more after ethanol ingestion - depending on cutoff, metabolism, and usage patterns. Under certain conditions, in-vitro (outside of the body, in the specimen container) formation of EtG may also occur when certain bacteria and ethanol or ethanol-producing bacteria are both present in a urine specimen. No published reports of in-vitro synthesis of EtS exist, however, even under the same conditions in which EtG may be synthesized in-vitro.EtS is typically present in urine at a lower concentration than EtG, although the ratio of EtG to EtS varies significantly between individual donors. In order to be reported positive for EtG, Quest Diagnostics’ clinical reporting criteria require that EtS be present in a specimen at a minimum concentration of 100 ng/mL whenever EtG is present at a concentration greater than or equal to 500 ng/mL.As with EtG, the presence of EtS in a urine specimen does not establish the source of the ethanol containing product and the possibility of "incidental exposure" and post-collection specimen changes needs to be considered when interpreting results. EtG and EtS testing, as with any controlled substance testing, measure only the presence and concentration of EtG (or EtS) in a given urine specimen. Quest Diagnostics recommends clinical correlation and/or healthcare provider review when interpreting EtG and EtS results.

Drug & Alcohol Testing

Theophylline is used in the treatment of bronchial asthma as well as in the treatment of chronic obstructive pulmonary disease and episodes of prolonged apnea in pre-term infants. Theophylline levels are monitored to assure adequate therapeutic levels are achieved and to avoid toxicity.

Drug & Alcohol Testing, Hormone Testing

Offered as part of multiple lab tests

Drug & Alcohol Testing, Hormone Testing

Offered as part of multiple lab tests

Drug & Alcohol Testing

Offered as part of multiple lab tests

Drug & Alcohol Testing

Offered as part of multiple lab tests

Drug & Alcohol Testing

Offered as part of multiple lab tests

Mental Health & Neurological, Drug & Alcohol Testing

This test may be used to detect exposure to or poisoning from organophosphate-based pesticides; to assess baseline levels before exposure to organophosphates; or to monitor cholinesterase levels in individuals who work with pesticides. This test is also used in the diagnosis of inherited pseudocholinesterase deficiency, for individuals with a family history who will be receiving the muscle relaxant succinylcholine during surgery.The Cholinesterase, Serum assay is often used as part of the diagnostic evaluation for individuals who present with symptoms of pesticide poisoning. Symptoms of organophosphate poisoning can range from mild to severe and may include sweating, salivation, miosis, hypotension, urinary incontinence, mental confusion, gastrointestinal spasms, anxiety, insomnia, tremors, convulsions, respiratory depression, and circulatory collapse, among others [1].This test is also used in the diagnosis of inherited pseudocholinesterase deficiency, an enzyme deficiency characterized by impaired metabolism of succinylcholine, a muscle relaxant for surgical anesthesia. Individuals with this disorder who receive succinylcholine are at risk for prolonged postsurgical apnea and paralysis lasting 2 or more hours [2]. Thus, testing may be helpful to evaluate individuals who present with these symptoms postsurgically, as well as those with a family history of pseudocholinesterase deficiency who are scheduled for surgery.References1. Lessenger JE, Reese BE.J Am Board Fam Pract. 1999;12:307-314.2. Soliday FK, et al.AANA J. 2010;78:313-320.

Drug & Alcohol Testing

Ethanol is the most commonly abused substance whose primary effect on the central nervous system varies with blood concentration. Not all individuals experience the same effects at a given blood level. Additionally, other central nervous system depressants can have an additive effect when taken in combination with ethanol. Approximately 5% of ethanol is excreted unchanged in urine. A positive urine ethanol result may suggest recent ethanol exposure and/or consumption; however, in diabetic patients with a urinary tract infection, ethanol is commonly present in urine as a result of glucose fermentation by yeast in the urine. When fermentation is not suspected, and urine ethanol is adjusted by a sample's creatinine concentration, urine ethanol may be used to estimate blood ethanol concentrations, as urine ethanol concentrations are approximately 130% of blood concentrations, if the patient is in the elimination phase. Caution should be exercised with interpretation of urine ethanol results; it is not recommended that a clinical decision be based solely on a urine ethanol result as there are several different scenarios that may have yielded the result.

Drug & Alcohol Testing

This assay is used for the detection of nicotine and cotinine in serum and plasma to determine the tobacco exposure status of the individual. Nicotine has a short half-life of approximately forty minutes; its presence may indicate recent tobacco exposure. Cotinine, the major nicotine metabolite, has a half-life of 24 hours and is detectable for several days after cessation of tobacco exposure.

Drug & Alcohol Testing

Offered as part of multiple lab tests

Drug & Alcohol Testing

Offered as part of multiple lab tests

Mental Health & Neurological, Drug & Alcohol Testing

True cholinesterase (RBC and plasma) activity is decreased in individuals with exposure to organophosphorous insecticides. True cholinesterase, found in erythrocytes and nerve tissue, is responsible for inactivating acetylcholinesterase at nerve endings. With decreased enzyme activity, patients may display a range of nervous system dysfunction. Analysis of RBC and serum or plasma activity is useful in monitoring exposure and recovery.

Drug & Alcohol Testing

This assay is used for the detection of nicotine and several metabolites and the related alkaloid anabasine in urine to determine the tobacco exposure status of the individual. Nicotine has a short half-life of approximately sixty minutes; Its presence may indicate recent tobacco exposure. The half-life of the various nicotine metabolites is longer and provides a larger window of detection for tobacco exposure. The presence of anabasine is indicative of tobacco exposure (smoked or smokeless) versus the use of a nicotine replacement patch product. Anabasine is a related alkaloid found only in the tobacco plant. Individuals exposed to passive tobacco smoke (environmental or second-hand) can have detectable concentrations of nicotine and its metabolites depending on the type of exposure. The ranges of concentrations related to passive exposure are not well established but normally are less than those attributed to active tobacco users.

Drug & Alcohol Testing

Valproic acid is used as an anticonvulsant to treat certain types of seizures, to prevent migraine headahces, and to treat various psychiatric illnesses such as bipolar disorder and aggression. Drugs that compete from protein-binding sites with valproic acid, can increase the concentration of valproic acid. Measurement of the free concentration is useful if toxicity is suspected.

Drug & Alcohol Testing

Ethyl glucuronide (EtG) and ethyl sulfate (EtS) are minor metabolite of ethanol metabolites and excreted in urine for a longer time than ethanol. Positive EtG and/or EtS test results thus provide a strong indication that the person has recently consumed alcohol, even when ethanol is no longer detectable. The test is a definitive assay using liquid chromatography mass spectroscopy (LC/MS/MS) methodology. Therapeutic urine drug monitoring of these metabolites is important for ensuring compliance to treatment strategies. Urine or oral fluid are the specimens of choice for routine monitoring of patients taking prescription drugs. Use of serum/plasma should be limited to anuretic patients, or where a patient's clinical appearance does not coincide with their prescribed medications. No single monitoring approach provides adequate information about the pattern or dose of patient drug use. Safest prescribing habits should include a combination of tools and laboratory test results to correctly detect drug use patterns.

Drug & Alcohol Testing

Oxcarbazepine is the prodrug for its active metabolite, 10-hydroxy-carbamazepine (MHD). MHD reaches maximal serum concentrations in three to five hours after oral ingestion and is 40% bound to protein. The elimination half-life is 8 to 15 hours.1Co-administration of other antiepileptic drugs (eg, carbamazepine, phenytoin, phenobarbital, primidone) causes decreases in MHD serum levels.2

Drug & Alcohol Testing

Oxcarbazepine (trileptal) is an anti-convulsant used for treating generalized tonic-clonic and partial seizures. It can be administered alone or as an adjunct to other anti-convulsants. Clinically significant effects of oxcarbazepine are observed when plasma levels of its active metabolite, 10-OH-carbazepine, are between 15 and 35 ug/mL. Toxic symptoms may occur when plasma levels exceed 35 ug/mL. The therapeutic monitoring of oxcarbazepine and its active metabolite are important for achieving proper serum/plasma concentration to inhibit epileptic seizures and avoid adverse effects. The precise mechanism of the action by which oxcarbazepine and its active metabolite exert their antiseizure effect is unknown. However, in vitro electro-physiological studies indicate that they produce blockade of voltage-sensitive sodium channels, resulting in the stabilization of hyperexcited neural membranes, inhibition of repetitive neuronal firing, and diminution of propagation of synaptic impulses. These are important in prevention of seizure spread in the brain. In addition, the increased potassium conduction and calcium channel activities may contribute to the antiseizure treatment effects. After oral administration, oxcarbazepine is readily absorbed in the body, followed by rapid and almost complete metabolization to 10-OH-carbazepine, active metabolite. The half-life of oxcarbazepine is only 1 to 2.5 hours, while that of 10-OH-carbazepine is 11 to 15 hours. The protein binding of oxcarbazepine is about 67%, whereas that of the metabolite is about 38%. The clearance of oxcarbazepine and its active metabolite from the body is mainly through ketone reduction and O-site conjugation with glucuronic acid rather than oxidative processes via cytochrome P450 system. More than 95% of the treatment dosage is excreted by the kidneys. Fecal excretion only accounts for less than 4%.

Drug & Alcohol Testing, Mental Health & Neurological

Offered as part of multiple lab tests

Drug & Alcohol Testing

Nortriptyline, a tricyclic antidepressant, is a derivative and metabolite of amitriptyline and is used to treat endogenous depression. The half-life of nortriptyline is 20 to 80 hours. Nortriptyline may be associated with cholestasis and cholestatic jaundice. Hematological consequences include agranulocytosis, purpura, and thrombocytopenia. Other side effects include a host of GI, endocrinologic, allergic, anticholinergic, cardiovascular, and neurologic disorders.All the tricyclic antidepressants have significantdrug interactions. Being potent inducers of hepatic drug-metabolizing enzymes, particularly CYP3A4, CYP1A2, and CYP2C9, the antiepileptic drugs, carbamazepine, phenytoin, phenobarbital, and primidone stimulate the oxidative transformation of concurrently prescribed antidepressants.1This results in decreased drug levels of the antidepressant. To a lesser extent, co-administration of oxcarbazepine, topiramate, and felbamate can also result in decreased antidepressant levels.Other tricyclic antidepressant drug interactions:hydrocortisone, methylphenidate, and phenothiazines increase tricyclic levels; tricyclics impair the antihypertensive effectiveness of clonidine and guanethidine; tricyclics and alcohol produce additive sedative effects, tricyclics and antiparkinsonism agents have potent anticholinergic side effects, and tricyclics and MAO inhibitors should not be co-administered because of the potential for antihypertensive and CNS crises.Tricyclics should be avoided in pregnant and lactating women because these drugs have not been established as safe. Geriatric patients are especially prone to postural hypotension, urinary retention, and sedation.2In general, it has been reported that, “Therapeutic drug monitoring of antidepressants allows us to take into account the influence of factors such as co-medications, diet, smoking habit, impaired organ function, and compliance. Therapeutic drug monitoring and genotyping are thus complementary, and their combined use contributes to improve pharmacotherapy with antidepressants and other drugs.”3

Drug & Alcohol Testing

Nortriptyline is a tricyclic antidepressant. Therapeutic drug levels are monitored to assist the physician assessing therapeutic response and to avoid toxicity.

Drug & Alcohol Testing

Offered as part of multiple lab tests

Drug & Alcohol Testing

Methadone possesses many of the pharmacologic properties of morphine and is approximately equipotent as an analgesic when administered parenterally. Unlike morphine, however, methadone produces marked sedative effects with repeated administration as a result of drug accumulation. This undesirable property restricted clinical usage of the drug until 1965 when Dole and Nyswander began narcotic maintenance treatment of former heroin addicts using large daily oral doses of dl-methadone.2Whereas maintenance patients may receive as much as 180 mg of the drug daily, doses ≤50 mg have been known to prove fatal to nontolerant adults. The pharmacologic activity is due almost entirely to the l-isomer. The d-methadone isomer does have analgesic properties in large doses and this may be due to conversion to minor amounts of α-l-methadone and α-l-normethadol, both of which are potent analgesics.

Drug & Alcohol Testing

Offered as part of multiple lab tests

Drug & Alcohol Testing

Offered as part of multiple lab tests

Drug & Alcohol Testing

Lacosamide is an antiepileptic medication. Monitoring the serum concentration is beneficial to ensure compliance with drug therapy.

Drug & Alcohol Testing

Offered as part of multiple lab tests

Drug & Alcohol Testing

The monitoring of the parent compounds and metabolites in urine of the group of drugs classified as Antidepressants.

Drug & Alcohol Testing

Offered as part of multiple lab tests

Drug & Alcohol Testing

Offered as part of multiple lab tests

Autoimmune & Inflammation, Drug & Alcohol Testing

In the absence of antiadalimumab antibodies, the adalimumab drug level typically reflects the total adalimumab concentration in serum. In the presence of antiadalimumab antibodies, the adalimumab level typically reflects the antibody-unbound fraction of adalimumab concentration in serum.This assay provides clinically valid antibody results at drug levels well above treatment targets (>30 μg/mL). Failure of adalimumab therapy may not always be due to the presence of antiadalimumab antibodies. In addition, the absence of antiadalimumab antibodies does not guarantee positive response to treatment.

Autoimmune & Inflammation, Drug & Alcohol Testing

In the absence of antiadalimumab antibodies, the adalimumab drug level typically reflects the total adalimumab concentration in serum. In the presence of antiadalimumab antibodies, the adalimumab level typically reflects the antibody-unbound fraction of adalimumab concentration in serum.This assay provides clinically valid antibody results at drug levels well above treatment targets (>30 μg/mL). Failure of adalimumab therapy may not always be due to the presence of antiadalimumab antibodies. In addition, the absence of antiadalimumab antibodies does not guarantee positive response to treatment.