The characteristics of stat laboratory tests.

We studied the use of stat (ie, statim--as soon as possible) laboratory tests at a university teaching hospital. For the 20 most frequently performed tests, 35.7% of the determinations were performed on a stat basis. The frequency with which a test was ordered on a stat basis ranged from 6.0% (for ESR) to 61.5% (amylase level). The proportion of laboratory test requests from a hospital service that were ordered stat ranged from 3.8% (orthopedic surgery) to 100% (emergency services). The daily number of regular laboratory test requests decreased significantly over the weekend, but the daily number of stat requests fell less sharply. The number of requests for routine tests decreased after 6 pm, but the number of requests for stat tests remained relatively constant until about midnight.