An Automated Method for the Recovery of Urinary Nitrogen in Nitrogen Balance Studies

[摘要] A method previously described for the total automation of nitrogen measurements from solid biologic material has been adapted for automating nitrogen recovery from urine following micro-Kjeldahl digestion. Standard solutions gave reproducible curves which were linear between the limits of 25 and 100 mg. of N2 ped liter. Comparative studies with the Markham ( 1 ) procedure revealed mean nitrogen recoveries for the automated method of 106%. The cause of the 6% difference remains unexplained, but cannot be attributed to low recovery by the Markham method. Application of a "correction factor" of 6% to the measurements by the automated method gave recoveries for urinary nitrogen almost identical with those obtained by the Markham method.Time studies were compared on the two methods. When the number of urine samples to be analyzed exceeded 14 per day, the automated method was time-saving, reliable, and convenient. It is suggested that the method described should replace the Markham procedure in central hospital laboratories or regional metabolic units in which more than 14 urinary nitrogen measurements are made daily.

[学科分类] 过敏症与临床免疫学