Effects of delayed examination on the results of certain hepatic tests.

NEED FOR INFORMATION concernng the validity of hepatic test results obtained from refrigerated blood or serum arose in connection with a blood donor screening program. As a part of this program, hepatic tests were applied to every donor reporting to the donation station for the purpose of excluding those carriers of viral hepatitis or others suffering from subclinical illnesses associated with disturbances in metabolism that cause abnormal response to such tests. Ordinarily these tests are applied to freshly collected blood serum; however, this was not feasible under the circumstances. Therefore, experiments were planned to show (a) whether refrigeration of serum caused changes that significantly altered test results, and (b) whether leaving serum in contact with cells overnight changed its behavior. Friedman reported that the zinc sulfate turbidities were lowered after refrigeration of sera (12). However, we have not found other reports on the effect of storage of serum or blood on hepatic tests.