The cost effectiveness of combined rapid tests (Multistix) in screening for urinary tract infections

Urinary tract infections (UTI) are relatively common in the urology outpatient's department and the renal transplant unit. Clinical diagnosis is imprecise and laboratory methods take time and are costly. Combined rapid tests (Multistix) were used to screen 400 consecutive mid stream specimens of urine: 200 from urology outpatients and 200 from renal transplant patients. All specimens were also tested in the laboratory. The negative predictive value for excluding UTI was excellent (> 98%) but positive predictive value for confirming presence of UTI was only 50%. However, with this simple screening method, up to 75% of urines can be excluded from laboratory analysis. Since there is a 20-fold difference in cost between dipstix and laboratory testing, the potential savings from this simple screening test is considerable.