Platelet Antibodies, Indirect
Ordering Recommendation

Not recommended for the diagnosis of immune thrombocytopenic purpura (ITP). Use to detect platelet-specific antibodies in suspected fetal or neonatal alloimmune thrombocytopenia, posttransfusion purpura, or multiplatelet transfusion refractoriness.

Semi-Quantitative Enzyme-Linked Immunosorbent Assay
1-3 days
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
ARUP Consult®
Disease Topics
Specimen Required
Patient Preparation
For newborns less than 30 days old, collect specimen from the mother. 
Serum separator tube (SST). 
Specimen Preparation
Separate serum from cells ASAP or within 2 hours of collection. Transfer 1 mL serum to an ARUP Standard Transport Tube and freeze. (Min: 0.5 mL) 
Storage/Transport Temperature
Frozen. Also acceptable: Refrigerated if maintained at temperature for 48 hours or less. 
Unacceptable Conditions
Microbially contaminated, heat-inactivated, hemolyzed, or lipemic specimens. 
Ambient: Unacceptable; Refrigerated: 48 hours; 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.

Hotline History
Component Test Code*Component Chart NameLOINC
0051062Platelet Antibodies, Indirect24375-8
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
  • Antiplatelet Antibodies
  • Antiplatelet, Circulating Platelet Antibodies
  • Circulating Platelet Antibody
  • HPA-la
  • Indirect Platelet Antibody
  • PLA-1
  • Platelet Antibodies, Qualitative
  • Platelet Antibody, Serum