Containment of pandemic infections mainly depends on prompt identification of carriers, achievable through strict surveillance and truthful diagnostic testing. Although molecular identification of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the gold standard method, its low sensitivity and long turnaround time are among major concerns. In this retrospective single-center study, we reviewed the results of the lymphocyte and neutrophil counts of 1450 Iranian patients with

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... avirus disease 2019 (COVID-19) recruited at Baqiyatallah Hospital, Tehran, Iran. Of 1450 patients, 439 cases (30.3%) were polymerase chain reaction (PCR) negative; further emphasizing that getting negative molecular testing is not as reliable as a positive result. While the lymphocyte count in cases with less than 50 years old was 1.8×103/µL (1.2-2.5), it was 1.47×103/µL (0.84-2.16) in the older group (p<0.001). Also, men experienced lower lymphocytes as compared to women (1.53×103/µL vs 1.76×103/µL; p=0.002). Of particular interest, the lymphocyte count in the PCR-negative cases was 1.77×103/µL (0.98-2.45) which was significantly higher than its count in their positive counterparts (1.53×103/µL; p=0.004). Unlike lymphocytes, sex and PCR did not significantly affect the number of neutrophils. The odds ratio for neutrophilia in patients aged older than 50, either with a negative or a positive PCR, was 2.46 and 2.23, suggesting old age as the most significant associated factor.