Table 4.
Percentage of patients with procalcitonin and C-reactive protein above threshold values
| Aetiology | PCT 0.1 ng/ml | PCT 0.5 ng/ml | CRP 10 mg/L | CRP 20 mg/L |
|---|---|---|---|---|
| %, 95 % CI | %, 95 % CI | %, 95 % CI | %, 95 % CI | |
| Dengue | 72 (67–77) | 25 (21–31) | 46 (40–52) | 28 (23–33) |
| Japanese encephalitis | 60 (50–69) | 32 (24–41) | 64 (55–73) | 52 (43–62) |
| Influenza | 34 (26–42) | 16 (11–24) | 49 (40–57) | 29 (22–37) |
| Rickettsial infections | 87 (82–91) | 53 (47–60) | 94 (90–97) | 80 (75–85) |
| Leptospirosis | 95 (91–98) | 65 (57–72) | 97 (92–99) | 92 (87–96) |
| Bacteraemia | 90 (82–95) | 71 (60–80) | 93 (85–97) | 86 (77–92) |
| Malaria | 96 (91–98) | 79 (72–85) | 93 (88–97) | 87 (80–92) |
In viral infections the proportion of patients with a raised procalcitonin level was consistently and significantly lower than that for CRP at 10 mg/L (p < 0.001). For the higher CRP threshold of 20 mg/L the differences in specificity were not significant, except in the case of Japanese encephalitis
Abbreviation: PCT Procalcitonin; CRP C reactive protein