A rapid turbidimetric method for the determination of cephalin-cholesterol flocculation is described. Greater specificity and photometric sensitivity have been achieved along with adequate precision. The test is standardized with the conventional barium sulfate turbidity standards used for other laboratory procedures. Definition of results in turbidity units is proposed, and photometric standardization of the cephalin-cholesterol emulsion described. The stability of the emulsion is elucidated. Comparison is made with a previously described quantitative method.