Blood

Adult Minimum: 5 mL
Pediatric Minimum: 2 mL

Specimen must be labeled with patient's first and last name and medical record number. Specimens will be rejected if information is not on the label when received.

0700-1400 Monday through Friday. All tests must be approved by the Clinical Pathology Resident (Pager 3404). The sample should be delivered by 10:00 a.m. for same-day testing. Result is accompanied by professional consultation and if indicated a platelet crossmatch with platelets in inventory will be performed to identify platelets for transfusion.

No reactivity.

This test is for patients known to be refractory to platelet transfusions. All tests must be approved by the Clinical Pathology Resident (Pager 3404).

This testing is used by the Blood Bank to determine whether platelet refractoriness may be immune-mediated. This is a screening test using the Immucor Capture-P assay to detect IgG antibodies against HLA or platelet antigens. Negative results indicate no detection of allo- or auto-antibodies to platelets. Positive results indicate detection of anti-platelet allo- and/or auto-antibodies. If variable reactivity is demonstrated with this test a platelet crossmatch is generally performed. In some cases, identification of HLA specific antibodies may assist in the identification of platelets for transfusions. This testing requires a separate order and is done by an outside reference laboratory. It generally takes take 3-5 days to receive HLA matched platelets. This test is not recommended for the diagnosis of idiopathic thrombocytopenic purpura (ITP) due to low sensitivity and specificity (Blood 1997 V89, Pg 1112).

This test does not detect non-immune causes of platelet refractoriness such as splenomegaly, DIC and bleeding. Our experience indicates this testing can identify platelets that are more likely to provide adequate increments (CCI>5) but in many cases crossmatched or HLA matched platelets fail to provide good CCIs.

Capture-P solid phase assay from Immucor. Platelet antigens (screen) or platelets in inventory (crossmatch) are captured on a well and incubated with patient serum. Antibody binding is detected using IgG coated indicator RBCs.

If specimen is received in the laboratory greater than 24 hours from time of collection and has not been refrigerated, it will be rejected.

Invert tube gently several times to mix blood.
Label transport tube with patient last name, first name, identification number, date and time of collection.
Do Not Centrifuge.
Submit whole blood in original container.

Room temperature or refrigerate if stored overnight.

Place requisition into outside pocket of bag.
Place specimen into zip-lock type bag, seal bag.
Place specimen into Styrofoam container, seal container.
Ship at room temperature.

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