Test ID: DIA
Diazepam and Nordiazepam, Serum
Secondary ID 
A test code used for billing and in test definitions created prior to November 2011
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
Assessing compliance
Monitoring for appropriate therapeutic level
Assessing toxicity
Method Name A short description of the method used to perform the test
High-Performance Liquid Chromatography (HPLC)
(Separate determinations are performed.)
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Aliases Lists additional common names for a test, as an aid in searching
Clorazepate (Tranxene)
Diazepam & Nordiazepam, S
Diazepam (Valium)
Nordiazepam (Tranxene)
Tranxene (Clorazepate)
Valium (Diazepam)
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Container/Tube: Red top
Specimen Volume: 3 mL
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | Mild OK; Gross reject |
| Lipemia | Mild OK; Gross reject |
| Icterus | Mild OK; Gross reject |
| Other | Serum gel tube |
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum Red | Refrigerated (preferred) | 14 days |
| Ambient | 14 days | |
| Frozen | 14 days |
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Benzodiazepine compounds, of which diazepam is a prototype, are widely used as antianxiety, hypnotic, and muscle relaxant agents. Diazepam (Valium) also is frequently used to treat status epilepticus, which is a state of rapidly recurring convulsive seizures that will not respond immediately to conventional anticonvulsant therapy. Although diazepam has been the benzodiazepine of choice for status epilepticus, recent evidence indicates that other drugs may be more beneficial because they provide longer control of seizures and produce less cardiorespiratory depression. Patients develop tolerance to diazepam, which requires that they be converted to phenobarbital or phenytoin within 24 to 48 hours of seizure control with diazepam.
Diazepam is administered intravenously or intramuscularly at a dose of 10 to 20 mg in adults to control recurrent seizures. It is rapidly absorbed, reaching peak plasma concentrations in 1 hour. Drug elimination follows a biphasic pattern with a rapid phase of 2 to 3 hours followed by a slow decay with a half-life of 2 to 8 days. After steady-state concentrations are achieved (in about a week), a half-life of 3 to 4 days is found. Diazepam has a volume of distribution of 1.1 L/kg, a half-life of 48 hours, and is 99% protein bound in serum.
Nordiazepam is the major metabolite of diazepam, tranxene, and prazepam, and can be differentiated from other benzodiazepines by gas-liquid chromatography (GLC). Nordiazepam has a blood half-life of 4 to 5 days.
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.
Therapeutic concentrations
Diazepam: 0.2-0.8 mcg/mL
Nordiazepam: 0.2-1.0 mcg/mL
Total of both: 0.4-1.8 mcg/mL
Toxic concentration
Total of both: > or =5.0 mcg/mL
Interpretation Provides information to assist in interpretation of the test results
For seizures:
Serum concentrations are not usually monitored during early therapy because response to the drug can be monitored clinically as seizure control. If seizures resume despite adequate therapy, another anticonvulsant must be considered.
For antianxiety and other uses:
-Therapeutic concentrations of diazepam are 0.2 to 0.8 mcg/mL
-After a normal dose of diazepam, tranxene, or prazepam, nordiazepam concentrations range from 0.4 to 1.2 mcg/mL
-Sedation occurs when the total benzodiazepine concentration is >2.5 mcg/mL
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
No significant cautionary statements
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
Reidenberg MM, Levy M, Warner H, et al: Relationship between diazepam dose, plasma level, age, and central nervous system depression. Clin Pharmacol Ther 1978;23:371-374
Method Description Describes how the test is performed and provides a method-specific reference
Diazepam is extracted from neutral serum into an organic phase that is then dried under nitrogen to concentrate the specimen. A small aliquot of the specimen is then analyzed by high-performance liquid chromatography (HPLC). (Kelly RC, Anthony RM, Krent L, et al: Toxicological determination of benzodiazepines in serum: methods and concentrations associated with high-dose intravenous therapy with diazepam. Clin Toxicol 1979;14:445-457)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Thursday; 9:00 a.m.
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
80154
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
| Result ID | Reporting Name | LOINC Code |
|---|---|---|
| 8629 | Diazepam, S | 3548-5 |
| 2475 | Nordiazepam | 3537-8 |
| 2459 | Diazepam and Nordiazepam | 16757-7 |
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