Adjustment by hematocrit level in calculation of removal rate in therapeutic apheresis.

Plasma volume variation during therapeutic apheresis (such as plasma exchange and selective plasma exchange using albumin solution as replacement solution or immunoadsorption plasmapheresis) has been considered to be unignorable. It changes the concentration of the target molecule and might impact its removal rate (RR.) This study aimed to evaluate the effects of plasma volume variation on the calculation of the RR of fibrinogen and immunoglobulin by categorizing the hematocrit (Ht) change during therapeutic apheresis into two patterns, i.e., increased group and decreased group. In all modalities of therapeutic apheresis, the Ht level frequently changed during apheresis sessions. In calculating RR, RR calculated with Ht adjustment was significantly higher than that calculated without adjustment in the increased group and significantly lower than it in the decreased group. Therefore, RR might have been underestimated in the increased group and overestimated in the decreased group when RR was calculated without Ht adjustment. Ht adjustment is suggested to be crucial in calculating RR in therapeutic apheresis. This article is protected by copyright. All rights reserved.