Introduction: Cancer patients are immunosuppressed and may present to an emergency department with atypical symptoms. In the emergency setting, it is important ascertain rapidly if lactic acid levels are high, either due to sepsis or tumor lysis syndrome, to effectively manage symptoms. Therefore, it is critical to determine the blood lactic acid level to timely identify who is at risk of sepsis and provide early intervention. We have compared blood lactic acid concentrations (BLAC) in cancer patients obtained by point-of-care testing (POCT) and those measured by laboratory analysis in blood samples drawn within a short time of each other.
Methods: This was a retrospective study in cancer patients whose BLAC had been determined by POCT and laboratory analysis. Only those patients who had blood withdrawn for both testing methods within a 2-h timeframe were included in the study. Regressions were performed together with an analysis categorizing the BLAC from both testing methods.
Results: A total of 274 patients met the criteria for the study. The BLAC from POCT correlated well with the values from laboratory testing (R = 0.925). Categorization of BLAC showed that 88.32% of the patients had BLAC that directly matched between the two tests; 28 (10.22%) patients had a normal BLAC according to laboratory analysis but a high BLAC on POCT; and four (1.46%) patients had a high BLAC according laboratory analysis but normal BLAC on POCT.
Conclusions: There was a high correlation between POCT and laboratory analysis values of BLAC in cancer patients, with the results from both testing methods agreeing 96% of the time. This finding suggests that POCT would suffice in most cases. Importantly, in 2% of the cancer patients who presented emergently, BLAC determined by POCT and laboratory analysis did not agree. Therefore, in subsequent decision-making, we recommend that if sepsis is suspected and BLAC determined by POCT is normal, nucleic acids, proteins, circulating cells, and interleukin-3 levels should also be obtained by POCT to confirm sepsis and/or rule out tumor lysis syndrome in patients with cancer.
Keywords: Cancer; Emergency department; Lactic acid; Point-of-care; Sepsis.