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PLATELET ANTIBODY, REFRACTORY TO PLATELET TRANSFUSION
MessagePlease contact Blood Bank for guidance in testing and managing patients who are not responding appropriately to platelet transfusion.
Test Code
LAB123150
CPT Codes
86022, CDM600877
Preferred Specimen
One 6 mL lavender top tube
Minimum Volume
3 mL(Adult)
2 mL (Pediatric)
2 mL (Pediatric)
Instructions
Tube must be appropriately labeled if intended for pretransfusion compatibility testing
Please refer to WVUH Transfusion Practice Policy (IV.139) and attachments for further information on transfusion practices.
Received in Sunquest by Blood Bank only.
Please refer to WVUH Transfusion Practice Policy (IV.139) and attachments for further information on transfusion practices.
Received in Sunquest by Blood Bank only.
Specimen Stability
Refrigerated: 24 hours
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Gross hemolysis or mislabeled specimen.
Methodology
Capture-P® Ready-Screen® Solid Phase System is used to detect IgG HLA and platelet-specific antibodies to platelets.
Setup Schedule
7:00 am-3:30 pm, Monday-Friday
Clinical Significance
Interpretive Information
Patients that have been alloimmunized through pregnancy or transfusion can develop antibodies that destroy platelets. Such antibodies, particulary those to HLA antigens, may be directed at determinants that occur with an incidence of 30% or less in the general population. Thus, screening tests for antibodies to platelets must include an adequate number of platelets to facilitate the detection of the most commonly encountered HLA or platelet-specific antibodies.
Capture-P® Ready Screen is a modified solid phase platelet antibody detection system. It provides dried, immobilized platelet membranes of thirteen group O donors in separate platelet coated wells. IgG HLA or platelet-specific antibodies that are present will bind to the platelet monolayer.
Interpretation:
For the test results to be considered valid, the following reactions must be obtained with the Capture-P® Control Sera:
• Positive Control-adherence of the Capture-P® Ready Indicator Red Cells to all or part of the reaction surface.
• Negative Control-button of the Capture-P® indicator Red Cells at the bottom of the test well.
The reactions are graded according to the table below.
Caution:
If the correct reactions are not obtained with the Capture-P® Control Sera, test reactions may be invalid and the tests on the plate must be repeated.
Patients that have been alloimmunized through pregnancy or transfusion can develop antibodies that destroy platelets. Such antibodies, particulary those to HLA antigens, may be directed at determinants that occur with an incidence of 30% or less in the general population. Thus, screening tests for antibodies to platelets must include an adequate number of platelets to facilitate the detection of the most commonly encountered HLA or platelet-specific antibodies.
Capture-P® Ready Screen is a modified solid phase platelet antibody detection system. It provides dried, immobilized platelet membranes of thirteen group O donors in separate platelet coated wells. IgG HLA or platelet-specific antibodies that are present will bind to the platelet monolayer.
Interpretation:
For the test results to be considered valid, the following reactions must be obtained with the Capture-P® Control Sera:
• Positive Control-adherence of the Capture-P® Ready Indicator Red Cells to all or part of the reaction surface.
• Negative Control-button of the Capture-P® indicator Red Cells at the bottom of the test well.
The reactions are graded according to the table below.
| Grade | Description |
| 4+ | Adherence is strong, covering entire monolayer |
| 3+ | Moderate to strong degree of adherence, adhering to approximately 3/4 of the monolayer surface with slight formation of red cells around the center of the well. |
| 2+ | Moderate degree of adherence, adhering to approximately 1/2 to 3/4 of the monolayer surface. Loosely formed red cell button with hole or tear. |
| 1+ | Slight to small degree of adherence, adhering approximately 1/4 of the monolayer surface. Diffuse red cell button |
| 0 | No red cell adherence, tightly defined red cell button. |
Caution:
If the correct reactions are not obtained with the Capture-P® Control Sera, test reactions may be invalid and the tests on the plate must be repeated.
Performing Laboratory
West Virginia University Hospital, Inc.
