- D3.524 - Clinical use of procalcitonin and IL-6 in diagnosis of bacterial superinfection in COVID-19

Medical treatment of COVID 19 has widespread spectrum of challenges in diagnostic approach as well as choice appropriate medical treatment. The cornerstone of pathophysiology is inflammation, and proteolysis of lung tissue, as well.  But previous issued articles report that viral inflammation in COVID 19 has no behavior like most viral respiratory infections. Pathogenesis of COVID 19 has large involvement of alveolar inflammation and proteolysis, and these facts remain the biggest problems of treatment, with mechanical ventilation or without. In the other hand inflammatory markers as IL-6 have no specificity. Procalcitonin is marker of bacterial inaction, which is very often seen as super infection in COVID 19. Aim of the study is to analyse whether procalcitonin and IL-6, as pro-inflammatory markers are useful for confirming bacterial superinfection of COVID 19 is the aim of this article.

Patients with COVID 19 infection treated in COVID Division of Pulmonary department. in General hospital Tešanj were analyzed. For all patients standard laboratory protocol was performed, including measurement of IL-6 and procalcitonin, with repetition of these analyzes as needed. Chest X-ray was performed for all patients on day of admission, on third, seventh day of hospitalization, and before discharge. Unscheduled Chest X-ray were performed if needed. Chest CT scan was performed as needed.

In period of 22 months 1654 patients was treated, 798 (%) female, and 854 (%) males with confirmed COVID 19 infection. Bacterial super infection was suspected if unexpected increase of temperature was registrated and substantial changes in Chest X-ray were seen, mostly if regional consolidation was present. Measurement of IL-6 and procalcitonin were repeated. Out of all, suspicious for bacterial superinfection was considered in 86 patients (5.29 %). Increased procalcitonin was present in 178 patients (10.76 %), and increased IL-6 in 112 those patients in which bacterial superinfection was suspicious (62.92 %).  Identification of bacterial infection was confirmed in 41 patients (47.75 %) in sputum specimen, and in the in 5 patients (5.81 %) hemoculture was positive.  

Increased procalcitonin can be used for confirmation of bacterial superinfection, but only with  substantial changes  on chest x-ray