Blood cholinesterase levels in the elderly and newborn.

The spectrophotometric method of Ellman was used to determine cholinesterase (ChE) levels in plasma and whole blood in elderly patients and umbilical cord blood of newborn infants. The mean +/- SD for plasma and whole blood ChE levels were 2.24 +/- 0.58 micromol/min/ml and 4.38 +/- 0.65 micromol/min/ml respectively in a group of healthy elderly patients (n = 25). The mean +/- SD for plasma and whole blood ChE levels were 2.23 +/- 0.77 and 3.31 +/- 0.56 respectively in cord blood of healthy full term newborn infants (n = 25). In a group of healthy adult blood donors the general mean +/- SD for plasma and whole blood ChE have been shown to be 2.71 +/- 0.75 and 4.87 +/- 0.73 micromol/min/ml respectively. Statistical analysis revealed that the mean levels of plasma and whole blood ChE in elderly, newborn infants and adults were different (p < 0.001). However, there was no statistical difference between the mean level of plasma ChE in elderly and cord blood but each shared statistically significant difference when compared to the mean level in adults. The mean activity of whole blood ChE in the 3 groups was different from one another. Theoretically, decreased levels of ChE would suggest a careful assessment of drugs that are hydrolysed by ChE.