Liver function tests: Difference between revisions

Revision as of 15:57, 9 September 2023

Revision as of 16:41, 9 September 2023

Line 20:

==Standard liver panel==

Standard liver tests for assessing liver damage include alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatases (APs). Bilirubin may be used to estimate the excretory function of the liver and coagulation tests and albumin can be used to evaluate the metabolic activity of the liver.<ref>{{cite web |last1=Gowda |first1name="Shivaraj |last2=Desai |first2=Prakash B. |last3=Hull |first3=Vinayak V. |last4=Math |first4=Avinash A K. |last5=Vernekar |first5=Sonal N. |last6=Kulkarni |first6=Shruthi S. |title=A review on laboratory liver function tests |url=https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2984286/ |website=The Pan African medical journal |pages=17 |date=22 November 2009}}<"/ref>

</br>Although example reference ranges are given, these will vary depending on method of analysis used at the administering laboratory, as well as age, gender, ethnicity, and potentially unrelated health factors. Individual results should always be interpreted using the reference range provided by the laboratory that performed the test.{{citation needed|date=July 2020}}

===Total bilirubin===

Line 41 ⟶ 42:

|}

Measurement of total [[bilirubin]] includes both unconjugated (indirect) and conjugated (direct) bilirubin. Unconjugated bilirubin is a breakdown product of [[heme]] (a part of [[hemoglobin]] in red blood cells). The liver is responsible for clearing the blood of unconjugated bilirubin, by 'conjugating' it (modified to make it water-soluble) through an enzyme named [[UDP-glucuronyl-transferase]]. When the total bilirubin level exceeds 17 μmol/L, it indicates liver disease. When total bilirubin levels exceed 40 μmol/L, bilirubin deposition at the sclera, skin, and mucous membranes will give these areas a yellow colour, thus it is called [[jaundice]].<ref name="Shivaraj 2009">{{cite journal|display-authors=3|last1=Shivaraj|first1=Gowda|last2=Prakash|first2=B Desai|last3=Vinayak|first3=V Hull|last4=Avinash|first4=AK Math|last5=Sonal N|first5=Venekar|last6=Shruthi S|first6=Kulkarni|title=A review on laboratory liver function tests|journal=The Pan African Medical Journal|date=22 November 2009|volume=3|issue=17|pages=17|pmid=21532726|pmc=2984286}}</ref>

The increase in predominantly unconjugated bilirubin is due to overproduction, reduced hepatic uptake of the unconjugated bilirubin and reduced conjugation of bilirubin. Overproduction can be due to the reabsorption of a [[haematoma]] and ineffective [[erythropoiesis]] leading to increased red blood cell destruction. [[Gilbert's syndrome]] and [[Crigler–Najjar syndrome]] have defects in the [[UDP-glucuronyl-transferase]] enzyme, affecting bilirubin conjugation.<ref name="Shivaraj 2009"/>