RT Journal Article
SR Electronic
T1 Complete blood count might help to identify subjects with high probability of testing positive to SARS-CoV-2
JF Clinical Medicine
JO Clin Med
FD Royal College of Physicians
SP e114
OP e119
DO 10.7861/clinmed.2020-0373
VO 20
IS 4
A1 Vincenzo Formica
A1 Marilena Minieri
A1 Sergio Bernardini
A1 Marco Ciotti
A1 Cartesio D'Agostini
A1 Mario Roselli
A1 Massimo Andreoni
A1 Cristina Morelli
A1 Giusy Parisi
A1 Massimo Federici
A1 Carla Paganelli
A1 Jacopo M Legramante
YR 2020
UL http://www.rcpjournals.org/content/20/4/e114.abstract
AB The SARS-CoV-2 pandemic has dramatically increased the workload for health systems and a consequent need to optimise resources has arisen, including the selection of patients for swab tests. We retrospectively reviewed consecutive patients presenting to the emergency department with symptoms suggestive of COVID-19 and undergoing swab tests for SARS-CoV-2. Complete blood counts (CBCs) were analysed looking for predictors of test positivity. Eight significant predictors were identified and used to build a ‘complete’ CBC score with a discriminatory power for COVID-19 diagnosis of AUC 92% (p<0.0001). When looking at the weight of individual variables, mean corpuscular volume (MCV), age, platelets and eosinophils (MAPE: MCV ≤90 fL, 65 points; age ≥45 years, 100 points; platelets ≤180×103/μL, 73 points; eosinophils <0.01/μL, 94 points) gave the highest contribution and were used to build a ‘simplified’ MAPE score with a discriminatory power of AUC 88%. By setting the cut-off MAPE score at ≥173 points, sensitivity and specificity for COVID-19 diagnosis were 83% and 82%, respectively, and the actual test positivity rate was 60% as compared to 6% of patients with MAPE score <173 points (odds ratio 23.04, 95% confidence interval [CI] 9.1–58.3, p-value <0.0001). In conclusion, CBC-based scores have potential for optimising the SARS-CoV-2 testing process: if these findings are confirmed in the future, swab tests may be waived for subjects with low score and uncertain symptoms, while they may be considered for asymptomatic or oligosymptomatic patients with high scores.