ARUP's Laboratory Test Directory

0051050: Platelet Antibodies, Indirect

Test Mnemonic: PLT ABSCRN
Methodology: Enzyme-Linked Immunosorbent Assay

Performed: Mon-Sat

Reported: 1-3 days

Specimen Required:  
Collect: One 7 mL plain red, one 5 mL lavender (EDTA) or pink (K2EDTA), or one 10 mL yellow (ACD Solution A).

Transport: 1 mL serum or plasma, frozen.  Submit specimen in an ARUP Standard Transport Tube.

Pediatric Collection/Transport: 0.5 mL serum or plasma, frozen. For newborns less than 30 days old, collect specimen from the mother.

Remarks: Separate serum or plasma from cells ASAP and freeze. Frozen serum or plasma is the specimen of choice, however, specimens that have been maintained at 2-8°C for 48 hours or less will be accepted.

Unacceptable Conditions: Microbially contaminated, hemolyzed, lipemic, or heat-inactivated specimens.

Stability: After separation from cells: Ambient: Unacceptable; Refrigerated: 2 days; Frozen: 1 month

Reference Interval:
None detected.

Interpretive Data:
This is the primary test for detection of platelet-specific antibodies.  It is not recommended for the diagnosis of immune thrombocytopenic purpura (ITP).  This test will detect both allo and autoantibodies, but will not distinguish between them. Results of this test should be used in conjunction with clinical findings and other serological tests.  Antibodies directed to antigens found on platelets are associated with many different clinical situations. Immune thrombocytopenic purpura (ITP) is a destructive thrombocytopenia caused by autoantibodies. Neonatal alloimmune thrombocytopenia (NATP) and post-transfusion purpura (PTP) are diseases where thrombocytopenia is caused by platelet-specific alloantibodies. HLA alloantibodies do not cause thrombocytopenia, but are commonly associated with refractoriness to platelet transfusions.

This test is designed to detect antibodies to platelet glycoproteins IIb/IIIa (HPA-1a/1b [PlA1 and PlA2], HPA-3a/3b, and HPA-4a), Ia/IIA (HPA-5a/5b), Ib/IX, and IV.  In addition, this test will also detect antibodies to HLA Class I antigens (HLA-A-B).

Testing for neonatal alloimmune thrombocytopenia should be performed using a maternal serum, since platelet antibody may not be detected in a neonatal serum.  False negative results are common in infant samples.



Note:
Further characterization of antibodies directed to platelet glycoproteins IIb/IIIa may be performed at client request by ordering Platelet Antibody Identification (0051051).

CPT Code(s):
86022

 

 

 
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