Alanine Aminotransferase (ALAT or GPT) and Aspartate Aminotransferase (ASAT or GOT) are the most important representatives of transaminases, which catalyze the conversion of α-keto acids into amino acids by transfer of amino groups. As a liver specific enzyme, ALAT is elevated in hepatobiliary diseases. Increased ASAT levels, however, can occur in connection with damages of heart or skeletal muscle as well as of liver parenchyma. 
Several meta-analysis identified elevated ALAT and ASAT values as one of the abnormal diagnostic markers in COVID-19 patients [2 - 4]. Increased ASAT levels were even linked with a high mortality rate . Liver injury has a potential clinical and biological significance in COVID-19 patients and might be directly caused by viral infection of liver cells or drug-induced liver injury. [6, 7]
Therefore, continuous monitoring of parameters, such as ALAT and ASAT is advised for prognostication purposes in COVID-19 patients. 
By empirically using cut-off levels for LDH and ASAT, Ferrari et al. was even able to identify COVID-19 positivity/negativity in almost 70% of patients. With the right panel of analytes and appropriate cut-offs, it could be possible in future to identify COVID-19 patients with high accuracy. A simple blood test could be an inexpensive, quick and easy alternative to rRT-PCR and especially beneficial for developing countries and countries suffering from shortage of rRT-PCR reagents. 
- Thomas L. Alanine aminotransferase (ALT), Aspartate aminotransferase (AST). In: Thomas L, editor. Clinical Laboratory Diagnostics. 1st ed. Frankfurt: TH-Books Verlagsgesellschaft; 1998. p.55-65.
- Rodriguez-Morales AJ, et al. Clinical, laboratory and imaging features of COVID-19: A systematic review and meta-analysis. Travel medicine and infectious disease, 2020, p. 101623.
- Henry BM, et al. Hematologic, biochemical and immune biomarker abnormalities associated with severe illness and mortality in coronavirus disease 2019 (COVID-19): a meta-analysis. Clinical Chemistry and Laboratory Medicine (CCLM) 1.ahead-of-print. 2020.
- Lippi G, Plebani M. Laboratory abnormalities in patients with COVID-2019 infection. Clinical Chemistry and Laboratory Medicine (CCLM) 1.ahead-of-print. 2020.
- Shi S, et al. Characteristics and clinical significance of myocardial injury in patients with severe coronavirus disease 2019. European Heart Journal, 2020.
- Zhang C, et al. Liver injury in COVID-19: management and challenges. The Lancet Gastroenterology & Hepatology, 2020.
- Sun J, et al. COVID‐19 and liver disease. Liver International, 2020.
- Lippi G, Plebani M. The critical role of laboratory medicine during coronavirus disease 2019 (COVID-19) and other viral outbreaks. Clinical Chemistry and Laboratory Medicine (CCLM) 1.ahead-of-print. 2020.
- Ferrari D, et al. Routine blood tests as a potential diagnostic tool for COVID-19. Clinical Chemistry and Laboratory Medicine (CCLM) 1.ahead-of-print. 2020.