Procalcitonin in the critically ill

Aim

To evaluate the diagnostic significance of procalcitonin (PCT) in critically ill patients and to compare its changes with changes of other acute phase reactants.

Methods

In 45 patients a total of 188 investigations of orosomucoid, alpha-1-antitrypsin, C-reactive protein (CRP), PCT, albumin, pre-albumin, cholinesterase, number of leukocytes, platelets, fibrinogen and indexed Quick's test (INR) were carried out. The investigations were repeated as requested by the clinical state. Also followed were the results of haemoculture, bacteriological investigations, the presence of the systemic inflammatory response syndrome (SIRS), frequency of sepsis, severe sepsis, septic shock and the number of organ failures. PCT was investigated by LUMItest-PCT-kit (BRAHMS Berlin, Germany), and other parameters by routine laboratory methods.

Results

From all investigated acute phase reactants only PCT and CRP offered the highest diagnostic and differentially diagnostic value. Therefore only these two parameters are presented in the following survey together with the number of leukocytes and temperature. Based on the criterion of the presence of apparent infection (no:yes [134:50 findings]) and positivity of bacteriological cultivation (no:yes [42:143]), there was a significant difference in PCT and temperature, but not in CRP or number of leukocytes. As for haemoculture positivity (no:yes [169:16]), a significant difference was only found for the temperature. For the presence of SIRS (no:yes [52:142]), the differences were significant for PCT, CRP, as well as for temperature and leukocytes.

MODS was divided according to the number of affected organs into categories 1–4 (number of findings 47:56:63:12). The found values: PCT (ng/ml) 0.9 ± 1.9, 1.4 ± 2, 3.2 ± 4.4 and 7.5 ± 5.9, and CRP (mg/l) 108 ± 65, 195 ± 129, 191 ± 165 and 130 ± 62. Out of all findings, 36 were classified as sepsis, 50 as severe sepsis and 48 as septic shock. In following the order parameter, its value in sepsis, severe sepsis and septic shock is presented. The significance of differences on the 1% level is marked; it is for sepsis:severe sepsis +, for sepsis:septic shock ++ and for severe sepsis:septic shock +++; on the 5% level the same symbols are in parentheses. Leukocytes (10⁹/l): 11.8 ± 4.9, 16.0 ± 7.6, 13.9 ± 8.8 (+, ++). CRP (mg/l): 128 ± 86, 191 ± 148, 204 ± 155 ([+], ++). PCT (ng/ml): 1.26 ± 2.31, 4.06 ± 6.46, 6.35 ± 11.91 (+, ++). Temperature (°C): 38.3 ± 0.7, 38.5 ± 0.8, 39.0 ± 1.2 (+, ++, +++).

Conclusion

PCT helps to distinguish the gravity of the patient's state as shown by different values in sepsis and severe sepsis or by its relations to MODS. The investigation of PCT is demanded for more accurate diagnosis of infected patients and in case of discrepancy between the clinical state and CRP.