Test ID: FPRTG
Prometheus TPMT Genetics
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.
Method Name A short description of the method used to perform the test
Polymerase Chain Reaction (PCR)
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
PRO-Predict TPMT FORWARD
Pro-PredictRx TPMT Genotype FORWARD
Prometheus TPMT Genetics FORWARD
Prometheus TPMT Genotype FORWARD
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: Lavender top (EDTA)
Specimen Volume: 5 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 | NA |
| Thawing | Warm reject; Cold reject |
| Lipemia | NA |
| Icterus | NA |
| Other | NA |
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 |
|---|---|---|
| Whole Blood EDTA | Refrigerated (preferred) | 30 days |
| Ambient | 8 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.
Reference Range: TPMT*1/TPMT*1
Prometheus TPMT Genetics is an analysis to determine an ability to produce thiopurine methyltransferase (TPMT) activity. It is a method to identify patients at risk for acute toxicity from 6-MP or azathioprine. This profile provides a breakdown of a patient’s genetics. The distribution of TPMT activity is trimodal; homozygous normal (89%), heterozygous (11%), and homozygous recessive (0.3%). Approximately 1 in 1213 individuals may have a low TPMT enzyme activity (homozygous low) resulting from known and theoretical mutations that are not included in this panel.
Notes: Genetic testing results are reported above as the individual allele present on each chromosome for three different polymorphisms; G238C, G460A, and A719G within the TPMT gene on chromosome 6. The alleles are numbered based on order of discovery.
A combination of Cepheid Smart Mix Reagents with ABI (Applied Biosystems Sequence Detection System) Prism 7500Fast allelic discrimination was used in determining the presence or absence of 3 polymorphisms of the TPMT gene located on chromosome 6. Included are 3 separate PCR reactions, 3 different sets of probes and primers. This test was developed and its performance characteristics determined by Prometheus Laboratories Inc. It has not been cleared or approved by the U.S. Food and Drug Administration.
The homozygous recessive genotype predicts a deficient capacity to produce TPMT enzyme activity. TPMT enzyme activity is essential for normal metabolism of azathioprine or 6-mercatopurine.
Our genotyping procedures will not distinguish between TPMT*1/TPMT*3A from the rare TPMT*3B/TPMT*3C which has a frequency of 1:120,890. This rare genotype is associated with low enzyme activity. Enzyme activity evaluation or sequencing is necessary to definitively identify this rare genotype.
Test Performed By: Prometheus Laboratories, Inc.
Therapeutics & Diagnostics
9410 Carroll Park Drive
San Diego, CA 92121-4203
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Lennard L et al: The Clinical Pharmacology of 6-Mercatopurine, European Journal of Clinical Pharmacology, Vol. 43, 1992, p 329-339
2. Charles R Yates et al: Molecular Diagnosis of Thiopurine S-Methyltransferase Deficiency: Genetic Basis for Azathioprine and Mercaptopurine Intolerance, Annals of Internal Medicine, Vol. 126, No. 8, April 1997, p 608-614
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.
Monday through Friday
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
Performing Laboratory Location The location of the laboratory that performs the test
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.
81401
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 |
|---|---|---|
| Z1518 | Prometheus TPMT Genetics | In Process |
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