THE USE OF A POLYMERASE CHAIN-REACTION AS A DIAGNOSTIC-TEST FOR ROCKY-MOUNTAIN-SPOTTED-FEVER

A polymerase chain reaction (PCR) for amplifying ribosomal DNA of Rick ettsia rickettsii was performed on blood clots and urine samples from 10 patients with suspected Rocky Mountain spotted fever (RMSF) and fiv e controls with nonrickettsial diseases. The results of this PCR-based procedure were positive in four of the five patients with probable RM SF, but reamplification was required in three patients. Rickettsia ric kettsii was grown from the blood of two of these four patients. The ur ine from one patient was also PCR-positive. These results confirm earl ier findings that the PCR can detect R. rickettsii, but the need for r eamplification indicates that the lack of sensitivity is a serious lim itation in the usefulness of the PCR as a clinical diagnostic test.