Abstract
BACKGROUND: The blood biomarkers GFAP (glial fibrillary acidic protein) and D-dimer have been shown to accurately diagnose large vessel occlusion ischemic stroke. The Upfront DX LVOne is a novel lateral flow-based point-of-care test used for the detection of GFAP and D-dimer. This study sought to (1) assess the performance of LVOne against commercially available point-of-care test platforms, which independently detect GFAP and D-dimer (Abbott iSTAT TBI Plasma and LumiraDx D-dimer), and to (2) assess the diagnostic performance of LVOne in large vessel occlusion detection.
METHODS: Manufacturer-reported detection thresholds of the LVOne test for GFAP and D-dimer (213 pg/mL and 600 ng/mL, respectively) were compared against commercial hospital-based point-of-care test platforms using 20 randomly selected plasma samples for each biomarker. D-dimer correlation between LVOne and LumiraDx was assessed using Spearman's Rank correlation coefficient; GFAP correlation between LVOne and the Abbott iSTAT TBI results were assessed using point biserial correlation. Diagnostic performance of the LVOne point-of-care test in conjunction with clinical assessment for detection of large vessel occlusion in plasma samples from 210 patients with suspected stroke was validated.
RESULTS: There was a strong positive correlation (Rho = 0.86, P<0.001) between the qualitative scoring of the lateral flow test and serum GFAP concentrations. Similarly, there was a significant positive correlation between the D-dimer quantification and LVOne semiquantitative measurements (Rho = 0.90; P<0.0001). In our cohort of 210 patients with suspected stroke, the LVOne test in conjunction with clinical assessment had a sensitivity of 75% (95% CI, 51%-91%), a specificity of 92% (95% CI, 87%-95%), a positive predictive value of 48% (95% CI, 30%-67%), and a negative predictive value of 97% (95% CI, 94%-99%) for detection of large vessel occlusion.
CONCLUSION: Our results validate detection thresholds for the LVOne test in a representative cohort of plasma samples of patients with suspected stroke. Further studies are required to demonstrate the efficacy, safety, and diagnostic performance of LVOne in capillary blood during emergency care/clinical triage.