The Use of Predictive Laboratory Tests in Rapid Triage of COVID-19 Pandemic Outpatient Clinic Patients.

Background: Patients who come to the emergency pandemic outpatient clinic with a pre-diagnosis of COVID-19 are still a burden on the health system. Rapid triage of patients is important to reduce transmission. The aim of this study is to evaluate the biochemistry and hemogram results of real-time reverse transcription-polymerase chain reaction (RT-PCR) positive and negative patients in the emergency pandemic outpatient clinic and to investigate predictive values of the initial tests that will help to make rapid diagnosis.

Methods: Patients who applied to the emergency pandemic outpatient clinic with the suspicion of COVID-19 between November 01, 2020 and January 01, 2021 were evaluated with RT-PCR and laboratory examinations.

Results: A total of 551 patients were included in the study. The mean age of the patients was 50.31 ± 18.47 (min. 18 - max. 94), and 47.2% (n = 260) of the patients included in the study were male and 52.8% (n = 291) were female. In the comparison of hemogram parameters, we found that mean platelet volume (MPV) was significantly higher (p = 0.023), whereas white blood cell (WBC), platelet counts (PLT), lymphocyte and neutrophil values were significantly lower in RT-PCR positive patients (p < 0.001). There were no significant differences between the PCR positive and negative patients in terms of other parameters. In the comparison of biochemical parameters, we found that lactate dehydrogenase LDH (p = 0.001), creatinine (p = 0.002), and AST (p < 0.001) values were significantly higher in PCR positive patients, while there were no significant differences in terms of other biochemical parameters (p > 0.05).

Conclusions: Our study results show that the practical quick-look hemogram and MPV can be used as a specially evaluated parameter in the rapid management of the first application COVID-19 patients. In addition, biochemically high levels of LDH and creatinine can be used to guide the clinician in terms of early hydration of the patient with a pre-diagnosis of COVID-19 to alleviate acute kidney damage.