RT Journal A1 WEINBERGER W T1 THymol as a source of error in heller's test for urinary protein JF Journal of the American Medical Association JO Journal of the American Medical Association YR 1909 FD April 24 VO LII IS 17 SP 1310 OP 1313 DO 10.1001/jama.1909.25420430006002b UL http://dx.doi.org/10.1001/jama.1909.25420430006002b AB It is a well-known fact that the ordinary tests for urinary proteins, especially for serum proteins, are not specific. Several concordant tests are necessary for satisfactory differentiation. Reliance on a single test often leads to error; a disturbing factor may prevent the detection of a substance that is present or may simulate the behavior of a substance that is absent. It is the object of this paper to present some observations on a disturbing factor in Heller's test.The tests most frequently used by the general practitioner for the detection of serum protein in the urine are: (1) The heat test—coagulation by boiling aided by a slight proportion of acid; (2) precipitation by potassium ferrocyanid in the presence of acetic acid, and (3) Heller's test—precipitation by concentrated nitric acid.As stated above, none of these reactions is specific for any of the serum proteins, the proteins in the urine about