Levin PD, Cohen MJ, Ohev-Zion E, et al. - Because procalcitonin (PCT) measurement has been suggested to direct antibiotic use, researchers investigated whether an increased sensitivity and specificity of PCT for diagnosing infection in intensive care unit patients can be achieved via repeated PCT measurements (0, 6, and/or 12 hours) vs the initial measurement only (time 0). In 67/176 (38%) patients, the infection was detected. With a cutoff value 0.5 ng/mL, the observed sensitivity of repeated vs the initial PCT measurement was 52/67 vs 46/67 and specificity was 60/109 vs 59/109. They concluded that the diagnostic accuracy of PCT was not improved to a clinically significant extent when repeat PCT evaluations over 12 hours were performed vs the initial single test.