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Platelet Antigen Genotyping Panel
Copy Utility
Assess risk for fetal and neonatal alloimmune thrombocytopenia. May be ordered for parental, fetal, or neonatal genotyping.
Polymerase Chain Reaction/Fluorescence Monitoring
Varies
7-14 days
Fetal Genotyping: Amniotic fluid OR cultured amniocytes. If the client is unable to culture amniocytes, this can be arranged by contacting ARUP Client Services at (800) 522-2787.
WITH Maternal Cell Contamination Specimen (see Note): Lavender (EDTA), Pink (K2EDTA), or Yellow (ACD Solution A or B).
Parental Genotyping: Lavender (EDTA).
Amniotic Fluid: Transport 10 mL unspun fluid. (Min: 5 mL)
Cultured Amniocytes: Transport two T-25 flasks at 80 percent confluency filled with culture media. Backup cultures must be retained at the client's institution until testing is complete.
Maternal Cell Contamination Specimen: Transport 3 mL whole blood. (Min: 1 mL)
Whole Blood (Parental Genotyping): Transport 3 mL whole blood. (Min: 1 mL)
Amniotic Fluid: Room temperature.
Cultured Amniocytes: CRITICAL ROOM TEMPERATURE. Must be received within 48 hours of shipment due to liability of cells.
Whole Blood or Maternal Cell Contamination Specimen: Refrigerated.
Fetal Specimen: Ambient: 48 hours; Refrigerated: Unacceptable; Frozen: Unacceptable
Whole Blood or Maternal Cell Contamination Specimen: Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable
Background Information for Platelet Antigen Genotyping Panel:
Characteristics: Spontaneous fetal intracranial bleeding may occur in 20 percent of pregnancies affected with severe perinatal alloimmune thrombocytopenia (PAT); there is a risk of fetal death. Post-transfusion purpura may occur in transfusion recipients with antibodies to a specific platelet antigen.
Incidence: PAT occurs in 1 in 5000 births.
Inheritance: For women homozygous for the less common "b" HPA allele with antibodies to the common "a" allele, there is a 50 percent risk a pregnancy will be affected if her partner is heterozygous for the "a" allele and 100 percent risk if her partner is homozygous for the "a" allele.
Cause: Maternal-fetal HPA incompatibility.
Polymorphisms Tested: HPA-1 (ITGB3, GPIIIa) c.176T>C, p.L59P; HPA-2 (GP1BA, GPIba) c.482C>T, p.T161M; HPA-3 (ITGA2B, GPIIb) c.2621T>G, p.I874S; HPA-4 (ITGB3, GPIIIa) c.506G>A, p.R169Q; HPA-5 (ITGA2, GPIa) c.1600G>A, p.E534K; HPA-6 (ITGB3, GPIIIa) c.1544G>A, p.R515Q; HPA-15 (CD109, CD109) c.2108C>A, p.S703Y
Clinical Sensitivity: Variable, dependent on ethnicity.
Methodology: PCR followed by fluorescent monitoring.
Analytic Sensitivity and Specificity: 99 percent.
Limitations: Bloody amniotic fluid specimens may give false-negative results because of maternal cell contamination. Diagnostic errors can occur due to rare sequence variations.
Informed consent: Recommended; forms are available at www.aruplab.com.
| PA 1-6, 15 Polymorphism | ||
|---|---|---|
| HPA System | "a" Allele Common | "b" Allele Variant |
| HPA 1 | T | C |
| HPA 2 | C | T |
| HPA 3 | T | G |
| HPA 4 | G | A |
| HPA 5 | G | A |
| HPA 6 | G | A |
| HPA 15 | C | A |
Laboratory Developed Test (LDT)
Maternal specimen is recommended for proper test interpretation if contamination of the fetal specimen from the mother is suspected. Order Maternal Cell Contamination.
Hotline History
81105; 81106; 81107; 81108; 81109; 81110; 81112
| Component Test Code* | Component Chart Name | LOINC |
|---|---|---|
| 3001171 | Platelet Antigen Geno Interpretation | |
| 3001173 | Platelet Antigen 1 Genotyping | |
| 3001174 | Platelet Antigen 2 Genotyping | |
| 3001175 | Platelet Antigen 3 Genotyping | |
| 3001176 | Platelet Antigen 4 Genotyping | |
| 3001177 | Platelet Antigen 5 Genotyping | |
| 3001178 | Platelet Antigen 6 Genotyping | |
| 3001179 | Platelet Antigen 15 Genotyping | |
| 3001180 | Platelet Antigen Geno Specimen |
- HPA platelet antigen genotyping panel
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