The effect of storage on the clinical utility of the immature platelet fraction.

The immature platelet fraction (%IPF) is a highly utilised new parameter in the full blood count (FBC) profile. It is a measure of the number of reticulated platelets and hence provides information on platelet transfusion requirements. It is common practice to measure %IPF values on blood samples that are several hours old, however unlike the well known good stability of other well established and more traditional FBC parameters such as haemoglobin and platelet counts, previous animal studies have shown that reticulated platelets are unstable. This study therefore assessed the validity of %IPF values obtained from stored patient samples. Our findings showed that %IPF values alter with storage; significant differences in %IPF values were obtained on stored samples compared with freshly analysed samples (p<0.001). It is therefore essential that in order to maintain the clinical utility of the %IPF, analyses should only be made on freshly drawn blood samples.