Cost analysis of laboratory tests in ambulatory primary care.

The cost of laboratory tests in the ambulatory primary care setting was analyzed to study relationships among cost to the patient, degree of abnormality of results, and physician follow-up of abnormal results. Laboratory fees constituted 32 cents of the total dollar for office charges. Considering only that portion of patient money spent for laboratory blood tests, 20 cents of the dollar went for tests with normal results, 25 cent for abnormals that were followed up by physicians, and 55 cents for abnormals that were not followed up. Separate analysis including only the abnormals was performed using two methods that differed as to whether or not low degree abnormals were considered worthy follow-up. Even when considering follow-up of this group unnecessary, 30 cents of the patient's dollar for abnormals was spent on appreciably high abnormal tests that were not followed up. This represents a substantial cost to the patient, from which no benefit can be envisioned.