The Reliability of the Albustix Test for Proteinuria.

Albustix (Ames Co.) provide a quick and simple test for proteinuria. These test papers are impregnated with tetrabromophenol blue and a citrate buffer ofpH 3; the indicator is yellow at thispH but changes to blue over thepH range 3-04-6. In the presence of protein the property of the indicator is changed (the so-called 'protein error') in such a way that it is blue atpH 3. A change of colour to blue therefore constitutes a positive reaction; it will be given not only by protein but also by urines which are alkaline enough to shift the pH of the buffer above about 4, and by conditions which leach out the buffer, such as leaving the paper immersed in urine for more than about one second or holding it in a stream of urine. Conversely,