The significance of trace proteinuria.
BACKGROUND
The clinical significance of a trace protein reading on urinalysis is unclear, and such a result is often ignored by the clinician.


METHODS
We examined 185 samples of urine with trace proteinuria by both Chemstrips and sulfosalicylic acid testing, and compared the results with those of urinary albumin and total protein concentrations.


RESULTS
Taking for the purposes of this study an arbitrary upper limit of normal of 20 mg/l for albumin and 100 mg/l for total protein concentration, we found abnormal albumin excretion in 87% and abnormal total protein excretion in 88% of trace samples. In this study, a negative urinalysis for protein excluded microalbuminuria in 87% and proteinuria in 78% of cases.


CONCLUSIONS
Qualitative testing for protein by urinalysis has a high sensitivity and specificity for diagnosing or ruling out microalbuminuria. Trace proteinuria usually means microalbuminuria; negative proteinuria tends to rule it out.
Division of Nephrology, Cook County Hospital, University of Illinois at Chicago and VAMC, West Side Division, Chicago, Ill. 60612, USA. Rsam29@aol.com
R
R
Sam
M S
MS
Shaykh
A A
AA
Pegoraro
V
V
Khalili
I
I
Hristea
A K
AK
Singh
J A L
JA
Arruda
G
G
Dunea
D000419:Albuminuria / Q000175:diagnosis*; D001557:Benzenesulfonates; D006801:Humans; D007674:Kidney Diseases / Q000175:diagnosis*; D011507:Proteinuria / Q000175:diagnosis; D011934:Reagent Strips; D012459:Salicylates; D012680:Sensitivity and Specificity; D016482:Urinalysis / Q000379:methods
D001557:Benzenesulfonates; D011934:Reagent Strips; D012459:Salicylates; C003366:sulfosalicylic acid