Background: Coronavirus disease 2019 (COVID-19) can cause a wide clinical spectrum, ranging from asymptomatic to severe disease with a high mortality rate. In view of the current pandemic and the increasing influx of patients into healthcare facilities, there is a need to identify simple and reliable tools for stratifying patients. Objective: Study aimed to analyze whether hemogram-derived ratios (HDRs) can be used to identify patients with a risk of developing a severe clinical form and admission to hospital. Methods: This cross-sectional and observational study included 500 patients with a confirmed diagnosis of COVID-19. Data on clinical features and laboratory parameters were collected from medical records and 13 HDRs were calculated and analyzed. Descriptive and inferential statistics were included in the analysis. Results: Of the 500 patients, 43.8% had a severe form of the disease. Lymphocytopenia, monocytopenia, higher C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) were found in severe patients (p < 0.05). Significantly higher neutrophil-to-lymphocyte ratio (NLR), derived NLR (dNLR), neutrophil-to-platelet ratio (NPR), neutrophil-to-lymphocyte-to-platelet ratio (NLPR) and CRP-to-lymphocyte ratio (CRP/Ly) values were found in severe patients (p < 0.001). In addition, they have statistically significant prognostic potential (p < 0.001). The area under the curve (AUC) for CRP/Ly, dNLR, NLPR, NLR, and NPR were 0.693, 0.619, 0.619, 0.616, and 0.603, respectively. The sensitivity and specificity were 65.7% and 65.6% for CRP/Ly, 51.6% and 70.8 for dNLR, 61.6% and 57.3% for NLPR, 40.6% and 80.4% for NLR, and 48.8% and 69.1% for NPR. Conclusion: The results of the study suggest that NLR, dNLR, CRP/Ly, NPR, and NLPR can be considered as potentially useful markers for stratifying patients with a severe form of the disease. HDRs derived from routine blood tests results should be included in common laboratory practice since they are readily available, easy to calculate, and inexpensive.

Background: A laboratory professional concerned with the quality of work in medical-biochemical laboratories ensures the accuracy and precision of laboratory analyses through the implementation of international and European guidelines for working with hazardous substances, through the availability and implementation of Standard Operating Procedures (SOPs). Laboratory hazards that affect the concentration and safety of workers arise from laboratory deficiencies such as: lack of preventive measures, knowledge and skills implemented through SOPs and good laboratory practice. Biophysical hazards in medical laboratories are manifested by needles and sharp objects, infectious materials, noise, vibration, radiation, poor air quality, temperature inversions. Objective: The aim of the research was to raise awareness of the quality of work in medical-biochemical laboratories in order to ensure the safety of workers. Methods: A cross-sectional questionnaire-based study was conducted among 100 laboratory proffesionals from Bosnia and Herzegovina (BiH) and Croatia. The research was conducted over a period of three months. Results: A higher percentage of exposure to infectious agents and needles and sharp objects was found among respondents from BiH compared to CRO (p=0.018 and p=0.001, respectively). We found that respondents employed in accredited laboratories are aware of exposure to hazards in a high percentage related to infectious agents, toxins (p=0.0012 and p=0.0046, respectively). A significant statistical difference was found between respondents with BiH and respondents with CRO in terms of knowledge of accreditation standards of medical-biochemical laboratories (p=0.0155). Respondents who have standard operating procedures available are aware of the hazards of infectious agents (p=0.0001), toxins (p=0.0466), needles and sharp objects (p=0.0052), noise (p=0.0030), vibration (p=0.0007) and extreme temperatures (p=0.0014). Conclusion: Efficient implementation and continuous compliance with the ISO 15189: 2018 standard requires constant commitment and active participation of laboratory staff. Laboratories must have standard operating procedures in place and actively monitor their use.