Are diagnostic tests repeated unnecessarily on hospital admission?

After admission to hospital, patients are often subjected to laboratory tests that may duplicate testing already done. For nearly 2800 patients at three hospitals the numbers and types of tests done in the week before and the week after admission were determined. A team of general practitioners judged the necessity of tests that had been repeated, with only those tests that had yielded normal results at both times being labelled as unjustifiably duplicated. Only 246 patients had had tests done in the week before entering the hospital, but 192 (71%) of them had had tests repeated after admission, 35 (14%) unjustifiably. Of the 743 laboratory tests performed before admission 447 (60%) were subsequently duplicated, but only 85 (11%) of them unjustifiably. Duplication, whether justifiable or unnecessary, was more likely to involve the hemoglobin determinations and urinalyses done routinely in hospitals.