• automated haematology analysers;
  • plasma;
  • platelet;
  • residual red blood cells;
  • transfusion

Background and Objectives  There is no automated, accurate assay for the enumeration of residual red blood cells (rRBCs) in non-RBC components for transfusion, despite the potential risk of allo-immunization when mismatched components are transfused.

Materials and Methods  The automated ADVIA 120 cerebrospinal fluid (CSF) assay, which is approved to count RBCs and WBCs in CSF samples, was optimized and tested to measure rRBC in platelet concentrate (PC) and plasma components.

Results  Sample dilution, incubation time and reagent volume were optimized for use with non-RBC blood products. The assay was linear (R2 = 0·99), even at low rRBCs counts. Intra- and inter-assay variation gave coefficients of variance (CV) between 2·2 and 9·4% and 2·6 and 14·9%, respectively, depending on rRBC levels. Good correlation (r = 0·995) was found between the automated assay and manual counting, which is considered the gold standard. Using the automated assay, the range of rRBCs (count/unit) in buffy-coat platelet concentrate (PCs) was 27–5505 × 106 and in apheresis PCs was 1–361 × 106.

Conclusion  The ADVIA CSF assay is a sensitive, precise and accurate means to assess rRBC counts in non-RBC components.