Automated and Manual Direct Methods for the Determination of Blood Urea

Abstract Automated and manual direct methods for the determination of urea in blood or serum are described. These methods determine urea by the colored product formed when urea, in relatively weak acid solution, reacts with diacetyl monoxime in the presence of thiosemicarbazide and ferric ion. Results are compared with those obtained by urease conversion of urea to ammonia and measurement of the ammonia by nesslerization.