Use of Sodium Measurement as a Surrogate Volume Measurement in Unmetered-Blood Collection Devices

Abstract

Tanaka et al. (1) describe a new blood-sampling device. Blood is applied to a membrane and travels laterally through the pores of the membrane. The red cells are trapped within the membrane and the serum can be recovered from the red-cell-free area. Some years ago we investigated this approach and encountered two problems. The first problem was hemolysis of red cells, which might interfere in the subsequent measuring process. This rendered measurement of some components (e.g., potassium and lactate dehydrogenase) impossible. Tanaka overcame this problem with the inclusion of sucrose in the membrane. The second problem we encountered was in the determination of the volume of serum extracted from the membrane to allow the use of unmetered-blood collection. Here we describe how we overcame …