Laboratory profiling of patients with long COVID in the Brazilian Amazon region: A cross‐sectional study

The condition commonly referred to as long coronavirus disease (COVID) is characterized by the continuation of symptoms, sometimes accompanied by new symptoms that persist after the resolution of acute coronavirus disease 2019 (COVID‐19). This observational cross‐sectional study investigated 332 patients with long COVID in the Brazilian Amazon region. The study aimed to elucidate the systemic interactions associated with long COVID by compiling the findings related to hematological, coagulation, immunological, metabolic, hepatic, renal, and muscular profiles. Participants with long COVID were identified using rigorous criteria and underwent thorough laboratory examinations. The obtained data were subsequently analyzed, allowing for comparisons, associations, and correlations between findings within distinct groups in the study. Significant associations were observed between hospitalization during the acute phase and persistent laboratory abnormalities, suggesting a potential link between acute severity and long‐term effects. Notably, individuals with long COVID for over a year exhibited elevated levels of monocytes, prolonged prothrombin times, reduced prothrombin activity, high levels of lactate dehydrogenase, and an increased frequency of qualitative C‐reactive protein detection. This study provides valuable insights into the laboratory risk profile of patients with long COVID, particularly in the unique context of the Amazon region, where patients exhibit persistent symptoms lasting up to 1261 days.