Transfusion medicine
Transfusion side effects
Platelet refractoriness

Author: Huy Phu Pham, M.D. (see Authors page)

Revised: 15 November 2017, last major update September 2011

Copyright: (c) 2002-2017, PathologyOutlines.com, Inc.

PubMed Search: Platelet refractoriness [title]

Cite this page: Pham, H.P. Platelet refractoriness. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/transfusionmedplateletrefract.html. Accessed December 12th, 2017.
Definition / general
  • Platelet refractoriness is the inability to get an adequate increase in platelet count after transfusion (Arch Pathol Lab Med 2003;127:409, Haematologica 2005;90:247)
  • Immune causes: antiplatelet or anti-HLA antibodies after multiple exposures from transfusion, pregnancy or transplantation (Transfusion 2005;45:761)
    • Usually occur within 21 - 28 days after primary exposure (pregnancy or transfusion) or 4 days after re-exposure
    • Anti-HLA antibodies causes 30 - 40% of platelet refractoriness
  • Nonimmune causes: usually due to platelet consumption
    • Fever, infection, drugs, bleeding, hypersplenism, DIC
  • Usually 4 - 6 units of platelets or 1 unit of apheresis platelets raises platelet count by 50 - 100K/μL; if no rise in platelet count after 1 hour, cause is likely immune mediated
  • If platelet count increases after 1 hour but drops after 24 hours, cause is likely consumption
Evaluation of platelet refractoriness
  • Determine if cause is immune or nonimmune mediated
  • Do at least 2, 1 hour posttransfusion platelet counts on consecutive days
  • Calculate the 1 hour CCI (body surface area × platelet count increment × 1011)/(number platelets transfused)
  • Platelet refractoriness is two 1 hour CCI of < 5,000 on consecutive days
  • If immune mediated, send for anti-HLA and anti-HPA antibody testing
Treatment
  • Initial step: give ABO identical platelets stored < 48 hours
  • ABO identical platelets and platelets from first degree relatives are helpful unless relatives may be source for stem cell transplantation
  • Determine anti-HLA and anti-HPA antibody
  • Select HLA matched or crossmatched platelets for transfusion to avoid crossreactive HLA or platelet antigens
  • IVIG may have short term benefit
  • Giving larger doses of platelets is usually not helpful if patient is bleeding (Blood 2005;105:4106)
  • Other potential therapies: immunosupression, rituximab, IVIG, plasma exchange, antifibrinolytic agents, recombinant factor VIIa
Prevention
Differential diagnosis