Manufacturing fault causes a false negative for haematuria using Makromed m81 urinalysis test strips: a case report

A 35-year-old male patient presented with painful gross macroscopic haematuria. Urinalysis using Makromed test strips showed a negative reading for blood. Subsequent laboratory analysis showed the presence of gross haematuria. A referral to a consultant urologist confirmed a diagnosis of renal stones. Subsequent investigations by the author indicated that a manufacturing fault was responsible for this error. Discussion with the manufacturer identified a fault in the packaging which led to photosensitive light degradation of enzyme pathways, resulting in a false negative finding. In situations when gross clinical findings are not supported by on -site diagnostic tests, the clinician should consider the possibility that the diagnostic tool is at fault and not the clinician. Makromed urine tests strips (MUTS) have been used in this practice for several years. There had been no previous concerns raised by any clinician within the group practice, nor by the Primary Care Trust, or any authoritative professional body. Argyropoulos et al. (2004) reported that renal stones cause haematuria in 92.9% of cases.