Post Transfusion Purpura Investigation

Test description

Post Transfusion Purpura (PTP) is a rare delayed transfusion reaction where a patient develops a sudden and dramatic drop in their platelet count typically between 6-10 days following red blood cell transfusion. Anti-HPA-1a antibody is most commonly associated with this reaction, however other HPA antibody specificities have also been found. Investigation for suspected PTP includes HPA antibody testing and HPA genotyping.

Post Transfusion Purpura Investigation (PDF)

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Specimen and requisition requirements

Specimen(s):
Three (3) full 5-7 ml EDTA (lavender) tubes mixed thoroughly by gentle agitation and one (1) 10mL SST serum tube inverted 5-10 times to activate clotting.

Label specimen(s) with the required minimum information: patient’s last name, first name, PHN/ (PHIN) or hospital name or other unique identifier, date of collection and facility name.

Complete Requisition (must include):

  • Patient's last name, first name, date of birth and PHN/(PHIN) or hospital number or other unique identifier
  • Facility Name
  • Physician/Health Care Provider name
  • Phlebotomist name, classification, initial
  • Date/time  of collection
  • Name, facility, address, contact number of individual to whom the report will be sent

Requisition(s)

Platelet Immunology Requisition (PDF)
(Electronic Fillable Form)

Pre-shipping storage

If unable to ship within 24 hours of collection store refrigerated at 1-10oC. Refrigerated samples must arrive within 48 hours of collection.

If unable to ship within 48 hours of collection; separate and freeze serum sample only.
Do not open EDTA Samples.

Shipping instructions

Contact the National Platelet Immunology Reference Laboratory (NPIRL) prior to shipping samples so that information may be obtained to assess the priority of the requested investigation.

Shipping
Ship in a container with an ice pack (gel pack stored at 2-8°C may be used for refrigerated samples).
Select shipping method for container to arrive at testing site within 24 hours.

Fax shipping information (way bill #) to 204-789-1186. Indicate the patient name and type of investigation on the fax.

Send to

Canadian Blood Services
Winnipeg Centre
National Platelet Immunology Reference Laboratory (NPIRL)
777 William Ave.
Winnipeg, MB R3E 3R4
Tel: 204-789-1152
Fax: 204-789-1186