The fat emulsion agglutination test: a reliable and cost effective alternative to the latex agglutination test for rapid bedside CRP measurement.

We compared two tests for bedside C reactive protein (CRP) measurement: the latex agglutination test (LAT) and the fat agglutination test (FAT). FAT is based on the property of CRP to agglutinate fat emulsions in the presence of CaCl2. The sensitivity, specificity and accuracy of FAT and LAT to detect a CRP > 10 mg/l, determined with radial immunodiffusion (n = 500 pediatric patients, CRP range 0- > 80 mg/l), were 91%, 82% and 90% respectively for FAT and 82%, 95% and 85% for LAT. FAT reagent could be stabilized with NaN3 (0.02%) for at least one year, when stored at 4 degrees C (n = 49). NaN3 (0.02%) had no effect on agglutination of FAT (n = 40). In conclusion, in pediatric patients, FAT is a reliable and cost effective alternative to LAT, if serum samples are used.