AST/ALT ratio

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AST/ALT ratio
LOINC16325-3, 1916-6
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AST/ALT ratio
LOINC16325-3, 1916-6

The AST/ALT ratio (aspartate transaminase–alanine transaminase ratio or aspartate aminotransferase–alanine aminotransferase ratio) is the ratio between the concentrations of aspartate transaminase (AST) (aspartate aminotransferase) and alanine transaminase (ALT) (alanine aminotransferase) in the blood of a human or animal. It is measured with a blood test and is sometimes useful in medical diagnosis to differentiate between causes of liver damage, or hepatotoxicity.[1][2][3]

Most causes of hepatocellular injury are associated with an AST that is lower than the ALT. An AST to ALT ratio of 2:1 or greater is suggestive of alcoholic liver disease, particularly in the setting of an elevated gamma-glutamyl transpeptidase.[4]

However, the AST to ALT ratio is occasionally elevated in an alcoholic liver disease pattern in patients with nonalcoholic steatohepatitis, and it is frequently elevated in an alcoholic liver disease pattern in patients with hepatitis C who have developed cirrhosis. In addition, patients with Wilson's disease or cirrhosis due to viral hepatitis may have an AST that is greater than the ALT, though the ratio typically is not greater than two.

Magnitude of AST and ALT elevations — The magnitude of AST and ALT elevations vary depending on the cause of the hepatocellular injury [16-19]. While values may vary in individual patients, the following are typical AST and ALT patterns:[5][6][7][8]

Alcoholic fatty liver disease: AST <8 times the upper limit of normal; ALT <5 times the upper limit of normal

Nonalcoholic fatty liver disease: AST and ALT <4 times the upper limit of normal

Acute viral hepatitis or toxin-related hepatitis with jaundice: AST and ALT >25 times the upper limit of normal

Ischemic hepatopathy (ischemic hepatitis, shock liver): AST and ALT >50 times the upper limit of normal (in addition the lactate dehydrogenase is often markedly elevated)

Chronic hepatitis C virus infection: Wide variability, typically normal to less than twice the upper limit of normal, rarely more than 10 times the upper limit of normal

Chronic hepatitis B virus infection: Levels fluctuate; the AST and ALT may be normal, though most patients have mild to moderate elevations (approximately twice the upper limit of normal); with exacerbations, levels are more than 10 times the upper limit of normal


Pathophysiology sample values
Na+ = 140Cl = 100BUN = 20/
Glu = 150
K+ = 4CO2 = 22PCr = 1.0\
HCO3- = 24paCO2 = 40paO2 = 95pH = 7.40
pACO2 = 36pAO2 = 105A-a g = 10
Ca = 9.5Mg2+ = 2.0PO4 = 1
CK = 55BE = −0.36AG = 16
PMO = 300PCO = 295POG = 5BUN:Cr = 20
UNa+ = 80UCl = 100UAG = 5FENa = 0.95
UK+ = 25USG = 1.01UCr = 60UO = 800
LDH = 100TP = 7.6AST = 25TBIL = 0.7
ALP = 71Alb = 4.0ALT = 40BC = 0.5
AST/ALT = 0.6BU = 0.2
AF alb = 3.0SAAG = 1.0SOG = 60
CSF alb = 30CSF glu = 60CSF/S alb = 7.5CSF/S glu = 0.4

It is also known as the "De Ritis Ratio",[9][10] named after De Ritis, who performed early analysis on transaminases.[10]


  1. ^ Nyblom H, Berggren U, Balldin J, Olsson R (2004). "High AST/ALT ratio may indicate advanced alcoholic liver disease rather than heavy drinking". Alcohol Alcohol. 39 (4): 336–9. doi:10.1093/alcalc/agh074. PMID 15208167. 
  2. ^ Nyblom H, Björnsson E, Simrén M, Aldenborg F, Almer S, Olsson R (September 2006). "The AST/ALT ratio as an indicator of cirrhosis in patients with PBC". Liver Int. 26 (7): 840–5. doi:10.1111/j.1478-3231.2006.01304.x. PMID 16911467. 
  3. ^ Gopal DV, Rosen HR (February 2000). "Abnormal findings on liver function tests. Interpreting results to narrow the diagnosis and establish a prognosis". Postgrad Med 107 (2): 100–2, 105–9, 113–4. doi:10.3810/pgm.2000.02.869. PMID 10689411. 
  4. ^ "Serum gamma-glutamyl transpeptidase and chronic alcoholism. Influence of alcohol ingestion and liver disease.". Dig Dis Sci 30 (3): 211–4. Mar 1985. doi:10.1007/bf01347885. PMID 2857631. 
  5. ^ "Ischemic hepatitis: widening horizons". Am J Gastroenterol 87 (7): 831–6. Jul 1992. PMID 1615936. 
  6. ^ "Ischemic hepatitis: clinical and laboratory observations of 34 patients". J Clin Gastroenterol 26 (3): 183–6. Apr 1998. doi:10.1097/00004836-199804000-00007. PMID 9600366. 
  7. ^ "Hypoxic hepatitis: clinical and hemodynamic study in 142 consecutive cases". Medicine (Baltimore) 82 (6): 392–406. Nov 2003. doi:10.1097/ PMID 14663289. 
  8. ^ Lok AS, McMahon BJ (February 2007). "Chronic hepatitis B" 45 (2). pp. 507–39. doi:10.1002/hep.21513. PMID 17256718. 
  9. ^ Kenneth D. McClatchey (2002). Clinical laboratory medicine. Lippincott Williams & Wilkins. pp. 288–. ISBN 978-0-683-30751-1. Retrieved 21 May 2010. 
  10. ^ a b De Ritis F, Coltorti M, Giusti G (July 2006). "An enzymic test for the diagnosis of viral hepatitis: the transaminase serum activities. 1957". Clin. Chim. Acta 369 (2): 148–52. doi:10.1016/j.cca.2006.05.001. PMID 16781697. 

See also[edit]