Tx. Zhao, CONTRIBUTIONS OF SUSPENDING MEDIUM TO ELECTRICAL-IMPEDANCE OF BLOOD, Biochimica et biophysica acta (G). General subjects, 1201(2), 1994, pp. 179-185
Blood cells from ten normal subjects, anticoagulated with dried sodium
heparin, were washed twice with phosphate-buffered saline (PBS) and r
esuspended with autologous plasma, serum, serum plus sodium heparin, a
nd PBS. The resistance R(p) and capacitance C-m of these suspensions w
ere determined by measuring the impedances at three frequencies 100 kH
z, 800 kHz and 1.2 MHz, and found to be dependent on the proteins and
electrolytes of the suspending medium. Two suspensions with the same m
edium resistivity might have different resistances if the contents of
the two mediums are different. The fibrinogen, serum proteins, sodium
heparin and membrane contributed to C-m by 20%, 14%, 2% and 64%, respe
ctively. For the samples with buffered sodium citrate as anticoagulant
and in the haematocrit range 30-60%, the group washed and resuspended
with PBS had a consistently decreased R(p) and C-m compared to the or
iginal group. Sodium heparin seemed to be the best anticoagulant when
studying the electrical impedance of blood. The influence of suspendin
g medium might result in part from the altered interfacial polarisatio
n. The results might be useful for understanding the origin of the imp
edance of blood, and imply that impedance measurement may be an altern
ative method for screening purposes for diseases that involve abnormal
compositions of certain plasma proteins.