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Optimum Timing of Blood Tests for Monitoring Patients With Clostridium difficile-Associated Diarrhea
  1. Aneel Bhangu, MBChB*,
  2. Adam Czapran, MBChB*,
  3. Sonia Bhangu, MBChB*,
  4. Devadas Pillay, MBChB
  1. From the Departments of *Surgery and †Microbiology, Good Hope Hospital,Birmingham, United Kingdom.
  1. Received November 2, 2009, and in revised form January 24, 2010.
  2. Accepted for publication January 24, 2010.
  3. The authors have no conflicts of interest to declare.
  4. Reprints: Aneel Bhangu, MBChB, Department of Surgery, Good Hope Hospital, Rectory Rd, Sutton Coldfield, Birmingham, UK. E-mail: aneelbhangu{at}


Objective This study aimed to identify optimum timing of blood tests and suitable cutoff values when managing patients with Clostridium difficile-associated diarrhea (CDAD), in relation to early mortality.

Methods Review of 204 patients treated as inpatients for a first episode of CDAD from January to December 2008. Differences in values during the first 7 days of CDAD for white cell count (WCC), albumin, C-reactive protein, and creatinine between those who died and survivors to 30 days were compared using Mann-Whitney U tests. Cutoff values were assessed using receiver operating characteristic curves.

Results Overall 30-day mortality was 27% (n = 56/204). White cell counts were significantly higher in those who died on the first 3 days (P < 0.001, P = 0.015, and P = 0.001, respectively). Median WCC in those who died was 20 × 109/L or greater on both days 1 and 2. Albumin was significantly different on day 1 only (P = 0.003); C-reactive protein, and creatinine did not differ significantly on any day. The highest WCC in the first 3 days produced an area under the curve of 0.718 (P < 0.001). A WCC cutoff at 20 × 109/L or greater when compared with 15 × 109 or greater had a higher positive predictive value (0.46 vs 0.34) and specificity (0.82 vs 0.60) but a lower sensitivity (0.49 vs 0.65). Mortality rates in the 2 groups were 46% and 34%, respectively.

Conclusions White cell count in the first 3 days is the strongest serum predictor of mortality and should be routinely monitored. A WCC of 20 × 109/L or greater may be the best cutoff value to objectively identify cases at higher risk of death.

Key Words
  • Clostridium difficile
  • diarrhea
  • hospital acquired infection
  • prognostic factors
  • monitoring

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