Hydroxyethyl starch serum levels in leukapheresis donors measured by modified periodic acid-Schiff staining technique

Hydroxyethyl starch (HES), a glucopyranose polymer used to enhance the yield of granulocytes during leukapheresis, was detected by periodic acid-Schiff (PAS) staining of 1-microliter samples following electrophoresis on thin agarose film. HES migrated with restricted electrophoretic mobility in the far gamma region, and the intensity of staining was found to be concentration dependent. Densitometer scanning showed a linear curve from 30 mg to 600 mg per dl, although bands were identified at concentrations lower than 30 mg per dl. Sera from 46 leukapheresis subjects showed the same restricted bands. HES measured retrospectively in sera obtained on days 1 to 400 following apheresis ranged from 675 to 30 mg per dl. The clearance of HES from the sera of four donors measured serially appeared biphasic with the first T1/2 of 0.4 to 6.4 days and the second T1/2 of 58 to 240 days. HES also was detectable in urine concentrated 100fold for as long as 7 days following leukapheresis . This simplified, and sensitive PAS glycoprotein staining method can be used to detect and follow HES concentrations in serum and may provide a new tool for the study of HES in leukapheresis donors.