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HelpTest Code BARBX Barbiturates Confirmation, Chain of Custody, Random, 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 always under the control of personnel involved with testing the specimen; 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, USpecimen Type
UrineSpecimen Required
Supplies: Chain of Custody Kit (T282)
Container/Tube: Chain of custody kit (T282) containing the specimen containers, seals, and documentation required
Specimen Volume: 10 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 less than 10 mL will compromise the ability to perform all necessary testing.
Specimen Minimum Volume
5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Urine | Refrigerated (preferred) | 14 days | |
| Frozen | 14 days | ||
| Ambient | 72 hours |
Reject Due To
| Gross hemolysis | OK |
| Gross icterus | 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 the personnel who collected, handled, and 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
Negative
Cutoff concentrations:
IMMUNOASSAY SCREEN
<200 ng/mL
GAS CHROMATOGRAPHY MASS SPECTROSCOPY:
Butalbital: <100 ng/mL
Amobarbital <100 ng/mL
Pentobarbital <100 ng/mL
Secobarbital <100 ng/mL
Phenobarbital <100 ng/mL
Interpretation
The presence of a barbiturate in urine indicates use of one 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.
Cautions
No significant cautionary statements
Clinical Reference
1. Baselt RC. Disposition of Toxic Drugs and Chemicals in Man. 10th ed. Biomedical Publications; 2014
2. Langman LJ, Bechtel LK, Holstege CP. Clinical toxicology. In: Rifai N, Chiu RWK, Young I, Burnham CAD, Wittwer CT, eds. Tietz Textbook of Laboratory Medicine. 7th ed. Elsevier; 2023:
Method Description
Preliminary screen is performed by immunoassay.
The barbiturate assay is based on the kinetic interaction of microparticles in a solution as measured by changes in light transmission. In the absence of sample drug, soluble drug conjugates bind to antibody-bound microparticles causing the formation of particle aggregates. As the aggregation reaction proceeds in the absence of sample drug, the absorbance increases. When a urine sample contains the drug in question, this drug competes with the drug derivative conjugate for microparticle-bound antibody. Antibody bound to sample drug is no longer available to promote particle aggregation, and subsequent particle lattice formation is inhibited. The presence of sample drug diminishes the increasing absorbance in proportion to the concentration of drug in the sample. Sample drug content is determined relative to the value obtained for a known cutoff concentration of drug.(Package insert: BARB. Roche Diagnostics; V 13.0, 09/2021)
The specimen is then analyzed by gas chromatography mass spectrometry for confirmation with quantitation.(Unpublished Mayo method)
Day(s) Performed
Monday, Wednesday, Friday
Report Available
3 to 5 daysSpecimen Retention Time
14 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
80345
G0480 (if appropriate)
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| BARBX | Barbiturates Confirmation, CoC, U | 53746-4 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 6668 | Barbiturates Immunoassay Screen | 70155-7 |
| 36143 | Butalbital-by GC/MS | 16237-0 |
| 36144 | Amobarbital-by GC/MS | 16239-6 |
| 36145 | Pentobarbital-by GC/MS | 16240-4 |
| 36146 | Secobarbital-by GC/MS | 16238-8 |
| 36147 | Phenobarbital-by GC/MS | 16241-2 |
| 36148 | Barbiturates Interpretation | 69050-3 |
| 36149 | Chain of Custody | 77202-0 |
Method Name
Immunoassay/Gas Chromatography Mass Spectrometry (GC-MS) Confirmation with Quantitation
Forms
1. Chain of Custody Request is included in the Chain of Custody Kit (T282).
2. If not ordering electronically, complete, print, and send a Therapeutics Test Request (T831) with the specimen.