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Test Code PLABN Platelet Antibody Screen, Serum

Useful For

Detecting alloantibodies to epitopes on platelet glycoproteins IIb/IIIa, Ib/Ix, Ia/IIa, IV and class I human leukocyte antigens to evaluate cases of immune mediated refractoriness to platelet transfusions, posttransfusion purpura, or neonatal alloimmune thrombocytopenia

Method Name

Solid Phase Enzyme-Linked Immunosorbent Assay (ELISA)

Reporting Name

Platelet Ab Screen, S

Specimen Type

Serum Red


Ordering Guidance


For neonate testing, consider sending a maternal specimen instead of a neonate specimen as unbound platelet antibodies may not be detected in the neonate serum.

 

This test is not recommended for the diagnosis of immune thrombocytopenia or autoimmune thrombocytopenia. Tests that are optimized to detect antibodies bound to the platelets will be useful in these situations; cell-bound platelet antibody (direct) test is strongly recommended.



Necessary Information


If ordering electronically, answer all prompt questions for timely result reporting:

1. Reason for request is required for result interpretation.

 a. Use provided diagnosis options if appropriate. If specific diagnosis is unknown, select the generic answer of alloimmune thrombocytopenia.

 b. Record only the diagnosis pertaining to this test.

 c. Record diagnosis description instead of code.

2. Indicate if patient has had intravenous immunoglobulin (IVIg) therapy in the last month: Yes or No



Specimen Required


Patient Preparation: Do not collect within 72 hours of a platelet transfusion. Transfused platelets will interfere with this assay.

Collection Container/Tube: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 1.5 mL

Collection Instructions: Centrifuge and aliquot serum into a plastic vial.


Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Red Frozen (preferred) 365 days
  Refrigerated  48 hours

Reject Due To

Gross hemolysis Reject

Clinical Information

Platelet antibodies may be allo- or autoantibodies and may be directed to a wide range of antigenic "targets" carried on platelet cytoplasmic membranes. Serum platelet antibody test is optimized to identify the presence of platelet alloantibodies in the patient.

 

Platelet alloantibodies are involved in several clinical situations such as:

-Immune mediated refractoriness to platelet transfusions usually due to antibodies to class I human leukocyte antigens and sometimes to antibodies specific to platelet antigens.

-Neonatal alloimmune thrombocytopenia

-Posttransfusion purpura, which are usually associated with platelet-specific antibodies

Reference Values

Not applicable

Cautions

This assay is intended for use as a screening assay. The results of this assay should not be used as the sole basis for a clinical decision. The reaction patterns a test sample produces with this product should not be relied on solely to establish the identity of a platelet antibody. Therefore, positive or negative results obtained using this assay should be used in conjunction with clinical findings or other serological tests.

 

Some low-titer, low-avidity antibodies may not be detected using this assay.

 

The presence of other human platelet antigen (HPA) polymorphic variants located on glycoprotein (GP)IIb/IIIa (HPA-6, 7, 8, 9, 10, 11, 14, 16, 17, 19, 20, 21), GPIa/IIa (HPA-13, 18), and GPIb/IX (HPA-12) has not been determined for the antigens captured in this kit. Antibodies to these systems may be reactive in this assay.

 

Antibodies to low incidence class I human leukocyte antigens may not be detected using this product.

 

This test has not been evaluated for the detection of autoantibodies to platelet antigens.

Clinical Reference

1. Kiefel V, Santoso S, Weisheit M, Mueller-Eckhardt C. Monoclonal antibody-specific immobilization of platelet antigens (MAIPA): A new tool for the identification of platelet-reactive antibodies. Blood. 1987;70(6):1722-1726

2. Moore SB, De Goey SR. Serum platelet antibody testing: evaluation of solid-phase enzyme immunoassay and comparison with indirect immunofluorescence. Am J Clin Pathol. 1998;109(2):190-195

3. Warkentin TE, Smith JW. The alloimmune thrombocytopenic syndromes. Transfus Med Rev. 1997;11(4):296-307

4. Metcalfe P, Watkins NA, Ouwehand WH, et al. Nomenclature of human platelet antigens. Vox Sang. 2003;85(3):240-245

5. Liebman HA. Immune thrombocytopenia (ITP): an historical perspective. Hematology Am Soc Hematol Educ Program. 2008;205

6. Kjeldsen-Kragh J, Killie MK, Tomter G, et al. A screening and intervention program aimed to reduce mortality and serious morbidity associated with severe neonatal alloimmune thrombocytopenia. Blood. 2007;110(3):833-839

7. Hoffbrand AV, Steensma D. Post transfusion purpura. In: Hoffbrand's Essential Haematology. 8th ed. Blackwell Publishing; 2019

8. Juskewitch JE, Norgan AP, De Goey SR, et al. How do I manage the platelet transfusion-refractory patient? Transfusion. 2017;57(12):2828-2835. doi:10.1111/trf.14316

9. Crighton GL, Scarborough R, McQuilten ZK, et al. Australian NAIT registry steering committee: Contemporary management of neonatal alloimmune thrombocytopenia: good outcomes in the intravenous immunoglobulin era: results from the Australian neonatal alloimmune thrombocytopenia registry. J Matern Fetal Neonatal Med. 2017;30(20):2488-2494. doi:10.1080/14767058.2016.1253064

Method Description

Patient serum is added to microwells coated with platelet and human leukocyte antigen (HLA) glycoproteins, allowing antibody, if present, to bind. Unbound antibodies are then washed away. An alkaline phosphatase-labeled antihuman globulin reagent (anti-IgG/A/M) is added to the microwells and incubated. The unbound anti-IgG/A/M is washed away and the substrate p-nitrophenylphosphate (PNPP) is added to the wells and incubated. The reaction is stopped with stopping solution. The optical density of the color that develops is measured in a spectrophotometer and results are interpreted.(Package insert: PakPlus. Immucor GTI Diagnostics; 303469.IFUEN Rev E; 07/2015)

Day(s) Performed

Monday through Friday

Report Available

2 to 4 days

Specimen Retention Time

7 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

86022

LOINC Code Information

Test ID Test Order Name Order LOINC Value
PLABN Platelet Ab Screen, S 95270-5

 

Result ID Test Result Name Result LOINC Value
PTL01 Overall Result 24375-8
PTL02 Interpretation 59466-3
PTL03 GPIIb/IIIa (Cell-1) 48505-2
PTL04 GPIIb/IIIa (Cell-2) 48505-2
PTL05 GPIa/IIa (Cell-1) 47084-9
PTL06 GPIa/IIa (Cell-2) 47084-9
PTL07 GPIb/IX 48506-0
PTL08 GPIV 87757-1
PTL09 HLA Class I 95269-7
PTL15 Reason for request? 29548-5
PTL16 IVIg in last month? 95268-9

Testing Algorithm

For more information see Platelet Antibody Testing Algorithm.

Secondary ID

35794

Interpretation

This assay screens patient sera for platelet-reactive antibodies via enzyme-linked immunosorbent assay.