Determination of urea in whole blood using a urea electrode with an immobilised urease membrane

A urea electrode using an ammonium ion-selective electrode with an immobilised urease membrane is described. The measurement of blood urea was carried out accurately without any pre-treatment of the samples. A conversion equation related to haematocrit was derived, which made it possible to determine plasma urea concentration from whole blood urea concentration. Rapid determinations of plasma urea concentrations were also made possible.