Biochemical and microscopic urinalysis: time and cost in a nephrology laboratory.

Background: Urinalysis is a fundamental test in internal medicine and nephrology. Figures for costs are available in the general laboratory, where biochemical and microscopic urinalysis are commonly performed as semiautomated screening tests. Information on costs is lacking in the nephrology laboratory, where a time-consuming morphological analysis is usually preferred. This study analyses the costs of urinalysis in a nephrology laboratory.

Methods: In the nephrology laboratory at the University of Turin - Italy, biochemical urinalysis consists of multi-property strip and proteinuria/creatininuria, done by laboratory technicians. Phase-contrast microscopy is done by a nephrologist or biologist. Time dedicated to the tests was recorded by the same operator over 20 working days, during which 350 urine samples were processed (median 19/day, range 842). The production costs were calculated with the logic bottom-up technique.

Results: Overall time needed was 11.9 minutes/sample. Biochemical urinalysis required 6.6 minutes/sample; time required and samples processed were inversely related (< or =19 samples: 7.95 minutes/sample; >19 samples: 5.6 minutes/sample, p=0.01). Microscopic urinalysis took 5.3 minutes/slide; the best time-to-samples ratio was at 18-22 samples per day (with peak efficiency at 21 samples: 4.6 minutes). Cost of reagents and disposables was Euro1.06/sample. Time accounted for euro 5.32/sample (technicians, nephrologist-biologist), with total direct cost of euro 6.38/sample.

Conclusion: In a nephrology laboratory, microscopic urinalysis is a time-consuming, expensive test. Analysis of cost and modalities may be useful, in a time of budget constrains, to maintain a role for this precious semeiotic art.