title: Counting platelets at transfusion threshold levels: impact on the decision to transfuse. A BEST Collaborative - UK NEQAS(H) International Exercise.
abstract: OBJECTIVE
  Obtaining accurate and precise platelet enumeration in automatic platelet analysers at low platelet counts is a challenge. To explore the performance of current haematology analysers in counting platelet concentrations usually used as platelet transfusion threshold.
  
  
  METHODS
  An international exercise where four blood samples with platelet levels near usual platelet transfusion thresholds was prepared and distributed.
  
  
  RESULTS
  The samples shipped had a platelet count of 6·3, 13·3, 21·6 and 53·0 × 10(9) /l according to the international reference method. We received 82 sets of results from nine countries. Instruments from six different manufacturers were represented. Although the mean count for each of the four samples was very similar to the values, according to the reference method (9·0, 16·2, 23·0 and 57·6 × 10(9) /l), significant variability in the results was found. Assuming that these were patient samples and the result of the count used to indicate a prophylactic platelet transfusion, undertransfusion would have occurred for 24·5% of the LP1 samples at a transfusion threshold of 10 × 10(9) /l and, at a threshold of 20 × 10(9) /l, undertransfusion would have occurred for 7·2% of the LP1 and 16·2% of the LP2 samples and overtransfusion would have occurred with 23·1% of the LP3 samples.
  
  
  CONCLUSIONS
  The results suggest that significant inaccuracy exists in counting low levels of platelets and that this inaccuracy might have a significant impact in under- and overtransfusion of platelet concentrates to patients.
authors: University Clinic Hospital, Barcelona, Spain.
authors: M
authors: M
authors: Lozano
authors: A
authors: A
authors: Mahon
authors: P F
authors: PF
authors: van der Meer
authors: S
authors: S
authors: Stanworth
authors: J
authors: J
authors: Cid
authors: D
authors: D
authors: Devine
authors: M K
authors: MK
authors: Fung
authors: B
authors: B
authors: de la Salle
authors: N M
authors: NM
authors: Heddle
mesh_terms: D000328:Adult; D000368:Aged; D001792:Blood Platelets / Q000502:physiology; D003657:Decision Making; D006801:Humans; D059021:Laboratory Proficiency Testing; D010976:Platelet Count / Q000592:standards; D017713:Platelet Transfusion; D015203:Reproducibility of Results
keywords: haematology analysers; low platelet count; platelet transfusion