The complete blood count and reticulocyte count - Are they necessary in the evaluation of acute vasoocclusive sickle-cell crisis?

Objective: To assess the usefulness of the complete blood count (CBC) and the reticulocyte count in the evaluation of adult patients with acute vasoocclusive sickle-cell crisis (SCC) presenting to the ED. Methods: A 2- part study was performed. Part 1 was a retrospective chart review of patients with a sole ED diagnosis of acute SCC. Part 2 was a prospective evaluation of consecutive patients presenting in SCC. In both parts of the study, patients with coexisting acute disease were excluded. The remaining patients were divided into 2 groups: admitted and released. The mean values for white blood cell (WBC) count, hemoglobin (Hb) level, and reticulocyte count were compared. In Part 2, the change (Δ) from the patient's baseline in WBC count, Hb level, and reticulocyte count also was determined. Data were analyzed by 2-tailed Student's t-test. Results: Part 1: There was no difference between the admitted (n = 33) and the released (n = 86) groups in mean WBC count (p = 0.10), Hb level (p = 0.25), or reticulocyte count (p = 0.08). Part 2: There was no difference between the admitted (n = 44) and the released (n = 160) groups in mean Hb level (p = 0.88), reticulocyte count (p = 0.47), ΔHb level (p = 0.88), and Δreticulocyte count (p = 0.76). There was a difference in mean WBC counts (15.8 ± 4.9 x 10⁹/L admitted vs 12.8 ± 4.9 x 10⁹/L released, p = 0.003) and ΔWBC counts (5.1 ± 4.6 x 10⁹/L admitted vs 1.8 ± 4.6 x 10⁹/L released, p < 0.002). Conclusion: Determination of the Hb level and the reticulocyte count do not appear useful in the evaluation of acute SCC in the ED. Admission decisions appear associated with elevations in the WBC count. Further study is required to determine the true value of the WBC count in such decisions.