Introduction: Although 80% of symptomatic individuals with COVID-19 develop mild forms, it is the severe (15%) and critical (5%) forms that have the greatest impact in the hospital setting. Recognizing markers that can predict severe forms is essential, especially in high-altitude populations. Methods: We conducted a prospective cohort study at 3200 masl (meters above sea level) in a city in Peru to determine if MPV (mean platelet volume) level is a predictor of COVID-19 severity. Patients with mild/moderate disease were enrolled and followed for 21 days or until the development of severe disease (primary outcome). A bivariate analysis was used to identify variables associated with severe disease. A ROC analysis determined the best MPV (mean platelet count) cut-off to predict COVID-19 severity, and then, a multiple regression analysis was performed. Results: 64 patients were enrolled. The median age was 48.5 years (IQT 39–64.5) and the proportion of women was 51.6%, the most frequent symptoms were chest pain (73%), fever (71%), and dyspnea (67%). The median time to develop a severe form from the onset of symptoms was 11 days (IQT 10.5–13). The most common radiographic phase on CT scan (computed tomography) was progressive (60.38%). We observed that an MPV of more than 10.15 fL in the first week of disease predicted severity regardless of age and sex at high altitudes. Conclusions: MPV in the first week of the disease may predict severity in patients diagnosed with COVID-19 at high altitudes; however, we need prospective studies with a larger population and at a different altitude, levels to confirm these findings.

Errors in the clinical laboratory are very frequent, most of which are mostly during the pre-analytical phase. That is why this research work proposes the identification of pre-analytical errors in the external office area of the Dos de Mayo National Hospital. To do this, a form was applied, filled out by the researcher at the time of supervision of the sampling. The instrument was validated by the joint recommendations of the EFLM-COLABIOCLI (European Federation of Clinical Chemistry and Laboratory Medicine) and the Latin American Working Group of the Pre-Analytical Phase (WG-PRE-LATAM) of the Latin American Confederation of Clinical Biochemistry. It was obtained as a result, among the most outstanding, that more than 90% of the patient was not recommended to rest for 5 minutes at the end of the phlebotomy, 80% did not register the identity of the phlebotomist in the request for examinations, in 40% there was a poor homogenization of the tubes, about 12% did not instruct the patient to apply pressure at the extraction site and 10% the barcode was not labeled in the presence of the tubes of the patient. It is concluded that the sampling personnel, phlebotomists, should follow the established standards and reinforce the previous knowledge through continuous supervision by the health personnel and pathologist.