Effects of Delayed Examination on the Results of Certain Hepatic Tests

Decreased thymol and zinc sulfate turbidity values often were observed after separated serum was refrigerated overnight. In some instances the changes were sufficient to affect appreciably the significance of the results. Phenol turbidity tended to increase considerably after refrigeration. Changes in thymol, zinc, and phenol turbidities were largely prevented by allowing serum to remain in contact with the clot during storage. The use of anaerobic technic in the collection and storage of serum also prevented changes in the thymol turbidity measurements and, to a lesser extent, in the zinc turbidity. However, a large change in phenol turbidity persisted under these conditions. The changes in zinc turbidity were related to the CO2 content of the sera being tested. Serum bilirubin concentration tended to decrease slightly during storage.