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Interpretive Handbook

Test 62741 :
Drug Screen, Prescription/OTC, Chain of Custody, Urine

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

This test looks for a broad spectrum of prescription and over-the-counter (OTC) drugs. It is designed to detect drugs that have toxic effects, as well as known antidotes or active therapies that a clinician can initiate to treat the toxic effect. The test is intended to help physicians manage an apparent overdose or intoxicated patient, to determine if a specific set of symptoms might be due to the presence of drugs, or to evaluate a patient who might be abusing these drugs intermittently. The test is not designed to screen for intermittent use of illicit drugs.


Drugs of toxic significance that are not detected by this test are: digoxin, lithium, and many drugs of abuse/illicit drugs, some benzodiazepines, and some opiates.


Chain of custody is a record of the disposition of a specimen to document who collected it, who handled it, and who performed the analysis. When a specimen is submitted in this manner, analysis will be performed in such a way that it will withstand regular court scrutiny.


See Prescription and Over-the-Counter (OTC) Drug Screens in Special Instructions.

Useful For Suggests clinical disorders or settings where the test may be helpful

The qualitative detection and identification of prescription or over-the-counter drugs frequently found in drug overdose or used with a suicidal intent


This test is designed to provide, when possible, the identification of all drugs present.


Chain of custody is required whenever the results of testing could be used in a court of law. Its purpose is to protect the rights of the individual contributing the specimen by demonstrating that it was under the control of personnel involved with testing the specimen at all times; this control implies that the opportunity for specimen tampering would be limited.

Interpretation Provides information to assist in interpretation of the test results

The drugs that can be detected by this test are listed in Prescription and Over-the-Counter (OTC) Drug Screens in Special Instructions.


Positive results are definitive.


Drugs of toxic significance that are not detected by this test include digoxin, lithium, many drugs of abuse/illicit drugs, some benzodiazepines, and some opiates. For these drugs, see Mayo Medical Laboratories' drug abuse surveys or drug screens or individual tests.


A detailed discussion of each drug detected is beyond the scope of this text. Each report will indicate the drugs identified. If a clinical interpretation is required, request a Drug/Toxicology Lab consult (Mayo Clinic patients) or contact Mayo Laboratory Inquiry (Mayo Medical Laboratories clients).

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Not intended for use in employment-related testing.


Not intended for therapeutic compliance testing.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.


Clinical References Provides recommendations for further in-depth reading of a clinical nature

1. Tietz Textbook of Clinical Chemistry. Third edition. Edited by CA Burtis, ER Ashwood. Philadelphia, WB Saunders Company 1999, pp 913-917

2. Disposition of Toxic Drugs and Chemicals in Man. Fifth edition. Edited by RC Baselt, RH Cravey. Foster City, CA, Chemical Toxicology Institute, 2000