alanine aminotransferase (ALT) in serum/plasma (SGPT)

From Aaushi
Jump to navigation Jump to search
[1][2][3][4][5][6][7][8][9][10][11][12]

Indications

Reference interval

  • Male & Female: 0 - 60 U/L

Principle

The Kodak Ektachem clinical Chemistry Slide (ALT) quantitatively measures alanine aminotransferase in serum or plasma.

The Kodak Ektachem Clinical Chemistry Slide (ALT) is a dry, multilayered analytical element coated on a clear polyester support. ALT is a MULTIPLE-POINT RATE test.

An 11 uL drop of patient sample is deposited on the Kodak Ektachem Clinical Chemistry Slide (ALT). The spreading layer, which evenly distributes the sample, also contains the ALT substrate L-alanine and sodium a-ketoglutarate. Alanine aminotransferase catalyzes the transfer of the amino group of L-alanine to a-ketoglutarate to produce pyruvate & glutamate. Lactate dehydrogenase (LDH) then catalyzes the conversion of pyruvate & NADH to lactate & NAD+.

The rate of oxidation of NADH is monitored by reflectance spectrophotometry. The rate of change in reflection density measured in a linear region is then converted to enzyme activity.

The following reaction sequences are involved:

Alanine + a-Ketoglutarate ------------> Pyruvate + Glutamate

Pyruvate + NADH + H+ ------------> Lactate + NAD+

Clinical significance

Transaminases are widely distributed in human tissues. High levels are found in liver & kidney with lesser amounts in skeletal muscle & heart. Trace ammounts are present in the skin, pancreas, spleen & lung. Activity in erythrocytes is 6-fold that in serum. ALT is largely a cytoplasmic enzyme.

ALT is normally present in human plasma, bile, CSF, & saliva, but none is present in urine unless a kidney lesion is present.

In viral hepatitis & other forms of liver disease associated with hepatic necrosis, levels of serum ALT are elevated even before the clinical signs & symptoms of disease, such as jaundice, appear. Activities for this enzyme may reach values as high as 100 times the upper reference limit, although 20 to 50 fold elevations are most frequently encountered.

ALT is a more liver-specific enzyme than AST. Serum elevations of ALT activity are rarely observed in conditions other than parenchymal liver disease. In contrast, elevation of serum AST may occur with myocardial injury, skeletal muscle injury or pulmonary injury & elevation of serum ALP is characteristic of biliary disease or cholestasis. 

ALT levels are within normal limits, or are only marginally increased, in uncomplicated myocardial infarction.  This enzyme is increased in liver damage secondary to heart failure.

In alcoholic hepatitis & after acute myocardial infarction, AST is generally > ALT. In viral hepatitis, ALT is generally > AST.

Increases

Decreases

Specimen

No special patient preparation is necessary.

For serum preparation: Collect the specimen by the standard venipuncture technique. Specimens are collected in a red top vacutainer by venipuncture & allowed to clot. Remove serum promptly from the clot & analyze as soon as possible. Avoid freezing the sample.

Minimum sample size is 0.5 milliliter: with an optimum size of 1.0 milliliters or larger.

Samples that have ALT values that exceed the analyzer dynamic range should be diluted with a Kodak Ektachem Solution (7% BSA)/Bovine Serum Albumin & reanalyzed. Multiply results by the dilution factor to obtain the original sample's ALT activity.

Interpretation

Management

More general terms

More specific terms

Additional terms

Component of

References

  1. ↑ Tietz, N., Fundamentals of Clinical Chemistry, 3rd Edition, W.B. Saunders Company, Philadelphia, 1987, p.370-371.
  2. ↑ Bauer,J./Ackerman,P./Toro,G., Clinical Laboratory Methods, 8th Edition, C.V. Mosby Company, St. Louis, MO., 1984, p. 493-498.
  3. ↑ Kodak Ektachem 700 Analyzer Operator's Manual, Kodak Clinical Products Division, Eastman Kodak Company, Rochester, New York.
  4. ↑ Package Insert, Kodak Ektachem Clinical Chemistry Product, Eastman Kodak Company, Rochester, New York.
  5. ↑ 5.0 5.1 5.2 5.3 Medical Knowledge Self Assessment Program (MKSAP) 11, 17. American College of Physicians, Philadelphia 1998, 2015.
  6. ↑ Clinical Diagnosis & Management by Laboratory Methods, 19th edition, J.B. Henry (ed), W.B. Saunders Co., Philadelphia, PA. 1996, pg 11.
  7. ↑ 7.0 7.1 7.2 Clinical Guide to Laboratory Tests, 3rd ed. Teitz ed., W.B. Saunders, 1995
  8. ↑ Dutta A et al. Variability in the upper limit of normal for serum alanine aminotransferase levels: A statewide study. Hepatology 2009 Dec; 50:1957. PMID: https://www.ncbi.nlm.nih.gov/pubmed/19787805
  9. ↑ Alanine Aminotransferase Laboratory Test Directory ARUP: http://www.aruplab.com/guides/ug/tests/0020008.jsp
  10. ↑ Panel of 15 tests Laboratory Test Directory ARUP: http://www.aruplab.com/guides/ug/tests/0020408.jsp
  11. ↑ Panel of 7 tests Laboratory Test Directory ARUP: http://www.aruplab.com/guides/ug/tests/0020416.jsp
  12. ↑ 12.0 12.1 Kwo PY, Cohen SM, Lim JK. ACG clinical guideline: evaluation of abnormal liver chemistries. Am J Gastroenterol. 2017;112:18-35. PMID: https://www.ncbi.nlm.nih.gov/pubmed/27995906

Patient information

alanine amiinotransferase (ALT) in serum patient information

Retrieved from "https://aaushi.info/w/index.php?title=A13135&oldid=1187805"