1 Children's Service, Massachusetts General Hospital, Department of Pediatrics, Harvard Medical School, Boston 02114
A source of false proteinuria was recently discovered when two female children were noted to have heavy "proteinuria" in clean voided urine specimens obtained in the Children's Service Ambulatory Clinic. The girls were admitted to the hospital a few days later. Repeated urine specimens were negative for protein in the hospital.
In an effort to explain this discrepancy, 5 drops of 10% sulfosalicylic acid were added to benzalkonium chloride solution which is routinely used to clean the genitalia in the [See Table I in Source Pdf.] Children's Clinic but not used on the wards. The benzalkonium chloride-sulfosalicylic acid mixture gave a 4+ precipitate indistinguishable from the 4+ protein reaction.