AST/ALT ratio

AST/ALT ratio
LOINC16325-3, 1916-6

The AST/ALT ratio is the ratio between the concentrations of the enzymes aspartate transaminase (AST) and alanine transaminase, aka alanine aminotransferase (ALT) in the blood of a human or animal. It is measured with a blood test and 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; however, 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 transferase.[4]

The AST to 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.

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 synthetic ability of the liver, and they may come from tissues other than liver (such as muscle).[5] For example, intense exercise such as weight lifting can increase ALT to 50-200 U/L, and AST to 100-1000 U/L (and raise AST to about 4 times ALT) for the week following the exercise.[6]

History

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

It is also known as the "De Ritis Ratio",[7][8] named after Fernando De Ritis, who performed analysis on transaminases in 1957.[8]

See also

References

  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. ↑ 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". Dig Dis Sci. 30 (3): 211–4. doi:10.1007/bf01347885. PMID 2857631.
  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.
  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. doi:10.1111/j.1365-2125.2007.03001.x. PMC 2291230. PMID 17764474.
  7. ↑ Kenneth D. McClatchey (2002). Clinical laboratory medicine. Lippincott Williams & Wilkins. pp. 288–. ISBN 978-0-683-30751-1. Retrieved 21 May 2010.
  8. 1 2 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.
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