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UW Health SMPH
American Family Children's Hospital

UW Hospital and Clinics Lab Test Directory

Test Name: Prothrombin Gene Mutation by PCR

Test Code(s): PTPCR / XPGM

CPT Code(s): 81240

Test Description: Test Component:

Prothrombin (G20210A) gene mutation analysis by real-time PCR amplification and melting point analysis

Methodology: Real-Time PCR followed by Melting Point Analysis

Clinical Significance: Detect presence of Prothrombin G20210A allele, which has been associated with elevated plasma prothrombin levels and moderately increased risk of first venous thrombotic events. Usually ordered in conjunction with Factor V Gene Mutation Analysis. The mutation of the prothrombin G20210A gene in the heterozygous state can confer an approximately 3 fold increased life-long risk for venous thrombosis. Due to low frequency, the G20210A mutation in the homozygous state and the additive effects of the G20210A mutation in combination with the Factor V mutation remains undetermined. Usually ordered with Prothrombin mutation is a test for Factor V Leiden mutation, which has been used to confirm the diagnosis of resistance to APC.

Days Performed: Once a week.

Turnaround Time: Routine: 10 days.

Specimen Requirements

Specimen: Blood

Collection Instructions: For UWMF - ordering source must fill out the UWMF Genetic Lab Request prior to specimen collection.

Collection Container: Preferred: Lavender top
Also Acceptable: Light blue top (3.2% NaCitrate)

Collection Volume: Preferred: 4 mL
Pediatrics: 2 mL

Sample Analyzed: Whole Blood

Volume Required: Preferred: 2 mL
Pediatrics: 1.2 mL

Specimen Transport: Transport specimen to Core Laboratory (B4/220) immediately. Refrigerate specimen if not delivered immediately. Transport on coolant pack if coming from outreach location; avoid freezing.  Specimen must be received within 7 days of collection date.

Stability: Ambient: 7 days
Refrigerated: 3 weeks
Frozen: Not acceptable


A written interpretive report is provided by the laboratory.

Additional Information:

This test was performed using a modification of an FDA approved method. The performance characteristics of this test were determined by the UWHC Clinical Laboratories and meet the standards for clinical testing.


A professional fee is associated with this test.

Prothrombin PCR G20210A
Prothrombin G20210A
Prothrombin 20210
Factor II Prothrombin G20210A

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