ABSTRACT
Background: Reverse transcriptase-polymerase chain reaction (RT PCR) testing is an important tool for the diagnosis of coronavirus disease 2019 (COVID19). However, performance concerns have recently emerged, especially about its sensitivity.. We hypothesized that clinical, biological and radiological characteristics of patients with false negative first RT-PCR testing, despite final diagnosis of COVID19, might differ from patients with positive first RT PCR. Methods: Case / control, multicenter study in which COVID19 patients with negative first RT PCR testing were matched to patients with positive first RT PCR on age, gender and initial admission unit (ward or intensive care). Results: Between March 30, and June 22, 2020, 80 cases and 80 controls were included. Neither proportion of death at hospital discharge, nor duration of hospital length stay differed between case and control patients (P=0.80 and P=0.54, respectively). In multivariate analysis, headache (adjusted OR: 0.07 [0.01 ; 0.49]; P=0.007) and fatigue/malaise (aOR: 0.16 [0.03 ; 0.81]; P=0.027) were associated with lower risk of false negative, whereas platelets > 207.103.mm-3 (aOR: 3.81 [1.10 ; 13.16]; P=0.034) and CRP > 79.8 mg.L-1 (aOR: 4.00 [1.21 ; 13.19]; P=0.023) were associated with higher risk of false negative. Interpretation: Patients with suspected COVID19 and higher inflammatory biological signs expected higher risk of false negative RT PCR testing. Strategy of serial RT PCR testings must be rigorously evaluated before adoption by clinicians.
