A simple spectrophotometric method for the quantification of residual haemoglobin in platelet concentrates.
OBJECTIVE
High levels of residual haemoglobin (Hb 0.1 g/l) are known to decrease the efficiency of pathogen-inactivation systems. We evaluated three separate methods to quantify Hb in platelet concentrates (PC).


METHODS
Nine PC prepared in platelet additive solution (PASIII) (median platelet yield of 283 x 10(9)/unit, range 46-353) were spiked to known Hb concentrations with whole blood and the samples were measured by using each of three methods: the 3,3',5,5'-tetramethylbenzidine (TMB) oxidation method (Sigma Diagnostics, 527-A); the Harboe spectrophotometric method; and the HemoCue plasma low-Hb photometer (PLHP).


RESULTS
The TMB and Harboe methods showed linear results compared to expected Hb (r2 > or = 0.981, P < 0.001) over the range tested (0.09-0.28 g/l) when the samples were haemolysed. The TMB method underestimated by an average of 6%, at and around 0.1 g/l Hb, compared to a 4% overestimation by the Harboe method and a threefold overestimation by the PLHP. The Harboe intra-assay coefficient of variation was < or = 1.85% across all concentrations, which contrasted with 30% at and around 0.1 g/l for the TMB method.


CONCLUSIONS
The Harboe spectrophotometric method is convenient, safe, accurate and reproducible, and outperforms the TMB and PLHP methods for quantification of residual Hb in PC.
Cookson
P
P
National Blood Service, England & North Wales, Essex, UK. phil.cookson@nbs.nhs.uk
Sutherland
J
J
Cardigan
R
R
D001793:Blood Preservation / Q000379:methods* / Q000592:standards; D004912:Erythrocytes / Q000473:pathology; D006454:Hemoglobins / Q000032:analysis*; D006461:Hemolysis; D006801:Humans; D008722:Methods; D017713:Platelet Transfusion / Q000592:standards*; D015203:Reproducibility of Results; D013057:Spectrum Analysis / Q000379:methods / Q000592:standards
D006454:Hemoglobins