AST/ALT ratio

AST/ALT ratio
LOINC16325-3, 1916-6

The AST/ALT ratio or De Ritis ratio is the ratio between the concentrations of two enzymes, aspartate transaminase (AST) and alanine transaminase, aka alanine aminotransferase (ALT), in the blood of a human or animal. It is used as one of several liver function tests, and measured with a blood test. It is sometimes useful in medical diagnosis for elevated transaminases to differentiate between causes of liver damage, or hepatotoxicity.[1][2][3]

Most causes of liver cell injury are associated with a greater increase in ALT than AST, but an AST/ALT ratio of 2:1 or greater is suggestive of alcoholic liver disease, particularly in the setting of an elevated gamma-glutamyl transferase.[4]

The AST/ALT ratio can also occasionally be elevated in a 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.[citation needed]

When the AST is higher than ALT, a muscle source of these enzymes should be considered. For example, muscle inflammation due to dermatomyositis may cause AST > ALT. This is a good reminder that AST and ALT are not good measures of liver function when other sources may influence AST and/or ALT, because they do not reliably reflect the synthesizing ability of the liver, and they may come from tissues other than liver (such as muscle).[5] For example, intense exercise such as weightlifting can increase ALT to 50–200 U/L, and AST to 100–1000 U/L (and raise AST to about four times ALT) for the week following the exercise.[6]

  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 and Alcoholism. 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 International. 26 (7): 840–5. doi:10.1111/j.1478-3231.2006.01304.x. PMID 16911467. S2CID 3126986.
  3. ^ Gopal DV, Rosen HR (February 2000). "Abnormal findings on liver function tests. Interpreting results to narrow the diagnosis and establish a prognosis". Postgraduate Medicine. 107 (2): 100–2, 105–9, 113–4. doi:10.3810/pgm.2000.02.869. PMID 10689411. S2CID 30483587.[permanent dead link]
  4. ^ Moussavian, S. N.; Becker, R. C.; Piepmeyer, J. L.; Mezey, E.; Bozian, R. C. (Mar 1985). "Serum gamma-glutamyl transpeptidase and chronic alcoholism. Influence of alcohol ingestion and liver disease". Digestive Diseases and Sciences. 30 (3): 211–4. doi:10.1007/bf01347885. PMID 2857631. S2CID 24588657.
  5. ^ Giboney, Paul T. (2005-03-15). "Mildly Elevated Liver Transaminase Levels in the Asymptomatic Patient". American Family Physician. 71 (6): 1105–1110. ISSN 0002-838X. PMID 15791889. Archived from the original on 2007-09-26. Retrieved 2020-11-23.
  6. ^ Pettersson, J.; et al. (2007). "Muscular exercise can cause highly pathological liver function tests in healthy men". British Journal of Clinical Pharmacology. 65 (2): 253–259. doi:10.1111/j.1365-2125.2007.03001.x. PMC 2291230. PMID 17764474.