EPO and polycythemia: We found that EPO-JAKPOT had high sensitivity (0.95; 95% CI 0.83–0.98) and a low −LR (0.07; 95% CI 0.02–0.30) for JAK2 mutant erythrocytosis, meaning that primary erythrocytosis could potentially be ruled out in an EPO-JAKPOT negative patient.