Plt Alloantibody, Basic (Sendout)

Test Information: This test is used to determine the underlying cause of poor platelet increment following a platelet transfusion.

Patients who fail to show an increase in platelet count after transfusion may be considered refractory to platelet transfusions. To ensure accurate interpretation, platelet counts should be checked within one hour of the transfusion.

The most common cause of a poor platelet response is non-immunologic factors, such as fever, splenomegaly, medications, sepsis, and other clinical conditions. It is important to consider these factors when evaluating platelet increments.

Another potential cause for insufficient platelet increment is the presence of HLA antibodies. HLA antibody testing can help identify alloantibodies in patients who are alloimmunized. These patients might benefit from receiving HLA matched platelets.

Antibody-positive patients who require HLA-matched platelets need to be HLA typed. If the patient has not been HLA-typed, contact the Immunogenetics/HLA Laboratory (206-689-6580) for sample requirements.

Ordering Note: A call-back number must be included for all STAT orders. Enter contact information in the Epic order comments or on the Bloodworks Northwest Requisition.

10 mL blood in YELLOW TOP (ACD) tube and 10 mL in RED TOP tube

• Also Accepted: 10 mL blood in YELLOW TOP (ACD) tube and 6 mL in RED TOP tube

Dual Signatures Required:

• At the time of collection, a two-person verification of positive patient identity must be performed in the presence of the patient by the person collecting the specimen and a second qualified staff member. This includes a verbal read back of the full legal name, spelling of the legal name, and MRN as it appears in the medical record.
• Both people performing verification must sign or initial the sample label(s).
• Write the collection date and time on the sample label.
• Signature of the person collecting the sample is requested on the Bloodworks Northwest form. (This is not required for testing as long as dual verification is documented on the sample label.)

Outside Laboratories:

• Store and transport whole blood at ambient temperature. Expedite transport.
• A completed Bloodworks Northwest Platelet Immunology Requisition or Immunogenetics/HLA Requisition must accompany all orders. In the Billing section, indicate "Bill to UWMC DLMP."

Stability: Ambient. Specimens must arrive at Bloodworks Northwest within 48 hours from draw time.

Store and transport samples at ambient temperature.

Sendouts (UW-MT/HMC) and FHCC SPS:

• Bloodworks NW HLA Test: 3630-00
• Interfaced: No
• Send sample(s) with a copy of the Bloodworks Northwest HLA Requisition or the EPIC requisition (must indicate the test or panel to be ordered at Bloodworks NW).
  • Package sample(s) with the associated requisition in a biohazard bag (one patient per bag). Orders received with multiple patient samples/requisitions in the same biohazard bag will be rejected by Bloodworks NW.
• Send routine samples via scheduled DLMP Courier pickups or Delivery Express according to the site’s preferred transportation method.
• STAT orders should be sent to Bloodworks Northwest as received.* Depending on the courier schedule, it may be necessary to individually batch a STAT order and/or call Delivery Express for pickup.
  • *STAT orders require the provider to request approval from the HLA Lab. If approval is obtained, the HLA Lead Technical Coordinator will contact CSS to request expedited transport of a sample. CSS will create an HC1 task for SPS. If this is not done, orders should be considered routine.

Stability: Ambient. Specimens must arrive at Bloodworks Northwest within 48 hours from draw time.