Adhesion of HbSS RBCs to immobilized ICAM-1 in vitro is associated with subject hematological parameters. (A) Subjects were categorized into 2 groups based on their LDH levels and ARCs; group 1 (●) had higher LDH and ARCs. The categorization was performed based on the k-means clustering method. The shaded green and blue regions indicate reference ranges (normal) for LDH and ARC levels, respectively. (B) Subjects in group 2 had significantly higher RBC adhesion levels compared with the patients in group 1 (mean, 3159 ± 4758 vs 453 ± 1159, respectively). (C) There is a positive correlation between adherent RBC numbers and WBC counts. The shaded blue region represents the normal WBC range in healthy adults. (D) Subjects with clinically high WBC counts (>11 × 10⁹/L) have significantly greater RBC adhesion to ICAM-1 in vitro. The horizontal lines in panels B and D represent the mean; ‘‘n’’ represents the number of subjects tested. The P values were calculated using the Mann-Whitney nonparametric U test. PCC, Pearson’s correlation coefficient.