Routine blood analysis greatly reduces the false-negative rate of RT-PCR testing for Covid-19
Davide Ferrari1, Eleonora Sabetta2, Daniele Ceriotti3
1SCVSA Department, University of Parma, Parma, Italy; 2 Laboratory Medicine Service, San Raffaele Hospital, Milano, Italy; 3 Vita-Salute University, San Raffaele, Milano, Italy; IRCCS Istituto Ortopedico Galeazzi, Milano, Italy. davide.ferrari@unipr.it.
Background:
The COVID-19 outbreak is now a pandemic disease reaching as much as 210 countries worldwide with more than 2.5 million infected people and nearly 200.000 deaths. Amplification of viral RNA by RT-PCR represents the gold standard for confirmation of infection, yet it showed false-negative rates as large as 15-20% which may jeopardize the effect of the restrictive measures taken by governments. We previously showed that several hematological parameters were significantly different between COVID-19 positive and negative patients. Among them aspartate aminotransferase and lactate dehydrogenase had predictive values as large as 90%. Thus a combination of RT-PCR and blood tests could reduce the false-negative rate of the genetic test.
Methods:
We retrospectively analyzed 24 patients showing multiple and inconsistent RT-PCR, test during their first hospitalization period, and compared the genetic tests results with their AST and LDH levels.
Results:
We showed that when considering the hematological parameters, the RT-PCR false-negative rates were reduced by almost 4-fold.
Conclusions:
The study represents a preliminary work aiming at the development of strategies that, by combining RT-PCR tests with routine blood tests, will lower or even abolish the rate of RT-PCR false-negative results and thus will identify, with high accuracy, patients infected by COVID-19.
