Lab Test

Platelet Glycoprotein Polymorphism Analysis (PL A1/A2)

Platelet Glycoprotein IIIa Polymorphism, Platelet Genotyping, Platelet Antigen A1/A2 (PLA), Platelet Glycoprotein PLA1/A1 Genotyping

Test Codes

EPIC: LAB6388, SOFT: GPLAG

Specimen Collection Criteria

Collect: One 10 mL whole blood in Lavender-top EDTA tube. (Minimum: 5.0 mL)

Physician Office/Draw Specimen Preparation

Do not freeze specimens. Maintain whole blood at room temperature (20-26°C or 68-78.8°F) or refrigerated (2-8°C or 36-46°F) prior to transport.

Preparation for Courier Transport

Transport: Whole blood at room temperature (20-26°C or 68-78.8°F) or refrigerated (2-8°C or 36-46°F). (Minimum: 5.0 mL whole blood)

Rejection Criteria

  • Frozen specimens. 
  • Unlabeled tubes. 
  • Specimens collected in heparin (Green-top), clot tubes (Red-top), or SST tubes.
  • This test will only be performed once in a lifetime for a patient.

In-Lab Processing

Do not freeze specimens. Maintain specimen refrigerated (2-8°C or 36-46°F) prior to testing.

Storage

Specimen Stability for Testing:

Whole Blood
Room Temperature (20-26°C or 68-78.8°F): 72 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): Unacceptable

Specimen Storage in Department Prior to Disposal:

Refrigerated (2-8°C or 36-46°F): 7 days

Laboratory

Royal Oak Clinical Molecular Pathology Laboratory

Performed

Once per week.
Results available in 7-10 days.

Reference Range

Wild type; Pl A1/A1 genotype.

Test Methodology

PCR (Polymerase Chain Reaction) followed by Restriction Fragment Length Analysis.

Interpretation

The presence of the Pl A2 allele (Pl A1/A2 heterozygosity and Pl A2/A2 homozygosity) is strongly associated with acute coronary thrombosis in patients of all ages (odds ratio 2.8); this association has been reported to be even stronger in patients with coronary events before the age of 60 years (odds ratio 6.2), and the risk appears to be compounded by smoking.

Clinical Utility

  • The presence of the Pl A2 allele of the platelet glycoprotein IIIa gene is associated with increased risk of acute coronary thrombosis.
  • Testing for PL A1/A2 genotyping is recommended for assessment of risk for acute coronary thrombosis in patients of any age, in patients with coronary events at a young age, especially patients who smoke, and in patients with family history of coronary artery disease at a young age. The test is also indicated in the workup of neonatal immune thrombocytopenia; this occurs when the mother is PL A1 negative and the fetus has inherited PL A1 from the father, resulting in maternal immunization against the platelet antigen PL A1.

CPT Codes

81400

Contacts

Last Updated

2/13/2020

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This directory currently reflects information only for specimens collected and/or processed at the
Farmington Hills, Grosse Pointe, Royal Oak, and Troy campuses.