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Test Code BARBX Barbiturates Confirmation, Chain of Custody, Urine

Useful For

Detecting drug abuse involving barbiturates such as amobarbital, butalbital, pentobarbital, phenobarbital, and secobarbital


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.

Additional Tests

Test ID Reporting Name Available Separately Always Performed
COCH Chain of Custody Processing No Yes
ADLTX Adulterants Survey, CoC, U Yes Yes

Testing Algorithm

Adulterants testing will be performed on all chain of custody urine samples as per regulatory requirements.

Reporting Name

Barbiturates Confirmation, CoC, U

Specimen Type


Specimen Required

Container/Tube: Chain-of-Custody Kit (T282) containing the specimen containers, seals, and documentation required.

Specimen Volume: 20 mL

Collection Instructions: Collect specimen in the container provided, seal, and submit with the associated documentation to satisfy the legal requirements for chain-of-custody testing.

Additional Information: Submitting <20 mL will compromise our ability to perform all necessary testing.

Specimen Minimum Volume

5 mL

Specimen Stability Information

Specimen Type Temperature Time
Urine Refrigerated (preferred) 14 days
  Frozen  14 days
  Ambient  72 hours

Reject Due To


Mild OK; Gross OK




Mild OK; Gross OK



Clinical Information

Barbiturates represent a class of drugs that were originally introduced as sleep inducers. Butalbital is also used to control severe headaches. Mephobarbital and phenobarbital are frequently used to control major motor (grand mal) seizures. These drugs are commonly abused as "downers" to induce sleep after an amphetamine- or cocaine-induced "high."


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.

Reference Values


Cutoff concentrations:



<200 ng/mL



<100 ng/mL



<100 ng/mL



<100 ng/mL



<100 ng/mL



<100 ng/mL


The presence of a barbiturate in urine at >200 ng/mL indicates use of 1 of these drugs.


Most of the barbiturates are fast acting; their presence indicates use within the past 3 days.


Phenobarbital, commonly used to control epilepsy, has a very long half-life. The presence of phenobarbital in urine indicates that the patient has used the drug sometime within the past 30 days.


No significant cautionary statements. This test is very specific for the compounds tested.

Method Description

Preliminary screen by immunoassay followed by gas chromatography-mass spectrometry (GC/MS) confirmation with quantitation.(Porter WH, Moyer TP: Clinical toxicology. In Tietz Textbook of Clinical Chemistry. Second edition. Edited by CA Burtis, ER Ashwood. Philadelphia, WB Saunders Company, 1994, pp 1162-1167)

Day(s) and Time(s) Performed

Monday through Friday

Analytic Time

2 days

Specimen Retention Time

2 weeks

Performing Laboratory

Mayo Medical Laboratories in Rochester

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information


G0480 (if appropriate)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
BARBX Barbiturates Confirmation, CoC, U In Process


Result ID Test Result Name Result LOINC Value
6668 Barbiturates Immunoassay Screen 70155-7
36143 Butalbital-by GC/MS 18385-5
36144 Amobarbital-by GC/MS 16190-1
36145 Pentobarbital-by GC/MS 16193-5
36146 Secobarbital-by GC/MS 16194-3
36147 Phenobarbital-by GC/MS 16241-2
36148 Barbiturates Interpretation 69050-3
36149 Chain of Custody No LOINC Needed

Method Name

Immunoassay/Gas Chromatography-Mass Spectrometry (GC-MS) Confirmation with Quantitation