Inability of community-based laboratories to identify pathological casts in urine samples
M. Rasoulpour, L. Banco, J. M. Laut and G. S. Burke
University of Connecticut School of Medicine, Farmington, USA.
OBJECTIVE: To determine the accuracy of microscopic examination of urine
from patients with known renal disease, performed by community-based
laboratories. DESIGN: Twenty-six urine specimens from 7 children with
Alport syndrome, lupus nephritis, and IgA nephropathy were simultaneously
submitted to 4 investigative sites: 2 community-based medical laboratories
(laboratories A and B), and the offices of 2 nephrologists (nephrologists C
and D). Participants A, B, and C were unaware of the nature of this
investigation and blinded to the diagnosis associated with each specimen.
RESULTS: Twenty-six specimens from 7 children were analyzed. Pathological
casts were identified in the 26 submitted specimens in the following order:
1 (4%) by laboratory A, 2 (8%) by laboratory B, 20 (77%) by nephrologist C,
and 26 (100%) by nephrologist D. Four-way and 3-way (A, B, C) comparisons
using the chi 2 test are significant at the P < .001 level. CONCLUSIONS:
The 2 community-based medical laboratories participating in this study did
not accurately identify pathological casts in urine specimens routinely
submitted to them. In addition to raising quality assurance issues, these
misleading reports may result in inaccurate diagnosis and unnecessary
laboratory and diagnostic investigations.
