False positive proteinuria may be reported on urinalysis if certain conditions are present.


Routine methods for measuring protein in the urine:

(1) dipstick, using tetrabromophenol blue

(2) sulfosalicylic acid


Causes of a false positive urine dipstick test for protein:

(1) urine with alkaline pH (pH > 8)

(2) highly buffered urine

(3) highly concentrated urine

(4) hematuria

(5) quaternary ammonium compounds (antiseptics or detergents)

(6) chlorhexidine (skin cleanser)

(7) unusual urine color


Causes of a false positive urine protein by sulfosalicylic acid testing:

(1) highly concentrated urine

(2) hematuria

(3) radio-opaque contrast agent

(4) antibiotics (sulfonamide, cephalosporin, penicillin)

(5) tolbutamide therapy

(6) pyridium (phenazopyridine)


To read more or access our algorithms and calculators, please log in or register.