Acute phase response detection and quantitation at the point of care in older adults with acute bacterial infections

Background. We investigated the reliability of a slide test in determining the presence of acute bacterial infections in a group of older adults to determine the usefulness of this test at the point of care. Methods. The study group included older adults with an acute bacterial infection and matched controls. We examined the white blood cell count (WBCC), the erythrocyte sedimentation, fibrinogen concentration, and high sensitivity C-reactive protein (hs-CRP), in addition to the slide test that reveals the number of leukocytes and degree of erythrocyte aggregation. Results. There were 144 patients and 144 controls at a respective mean ± standard deviation age of 71.3 ± 20.7 and 70.6 ± 20.2 years. A highly significant difference was noted between patients and controls in all laboratory markers, both conventional and those obtained by the slide test. By using hs-CRP, we correctly predicted the individual group as control or bacterial infection. When analyzed by means of a receiver-operated characteristic (ROC) curve, hs-CRP was again most reliable, with the slide leukocyte test being superior to the WBCC. Conclusion. The slide leukocyte count provided a similar diagnostic yield to that of the WBCC. The availability of this slide test at the point of care will provide the clinician with a useful biomarker when faced with clinical decisions in the care of older adults.