We measured the time interval from result entry by the clinical laboratory to inquiry for reports by clinicians as a proxy for the actual turnaround time required to meet current patient care needs and to determine whether different patterns of report inquiry occur among clinical departments. The study included 4,004 complete blood cell (CBC) count reports that were sought by the clinical services using the hospital information system. The median time to report inquiry was 90 minutes for routine inpatient tests, 35 minutes for stat inpatient tests, and 30 minutes for the stat outpatient CBC counts. Most reports (range, 86%-94%) from these three subgroups were requested within 4 hours from entry of the results in the hospital information system. Of the routine outpatient test reports, 14%, 23%, and 31% were requested within the first 2 hours, 4 hours, and 8 hours, respectively. Although the interdepartmental variations in the median time for report inquiry were statistically significant for routine inpatient tests, stat inpatient tests, and stat outpatient tests, inquiries for the preponderance of reports for all three groups were within the first 1.5 to 3 hours from entry of the results in the hospital information system. We conclude that the majority of CBC counts and other tests with effects on immediate patient care management must be performed very rapidly on site and cannot be moved off site without compromising current standards of medical practice.