Liver function tests: Difference between revisions

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Revision as of 06:21, 18 December 2022

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'''Liver function tests''' ('''LFTs''' or '''LFs'''), also referred to as a hepatic panel, are groups of blood tests that provide information about the state of a patient's [[liver]].<ref name="Lee2009">{{cite book|last=Lee|first=Mary|title=Basic Skills in Interpreting Laboratory Data|url=https://books.google.com/books?id=AUSIRcV_as0C&pg=PA259|access-date=5 August 2011|date=2009-03-10|publisher=ASHP|isbn=978-1-58528-180-0|page=259}}</ref> These tests include [[prothrombin time]] (PT/INR), [[activated Partial Thromboplastin Time|activated partial thromboplastin time]] (aPTT), [[albumin]], [[bilirubin]] (direct and indirect), and others. The liver transaminases [[Aspartate transaminase|aspartate transaminase (AST or SGOT)]] and [[Alanine transaminase|alanine transaminase (ALT or SGPT)]] are useful biomarkers of liver injury in a patient with some degree of intact liver function.<ref name="pmid10221307">{{cite journal | author = Johnston DE | title = Special considerations in interpreting liver function tests | journal = Am Fam Physician | volume = 59 | issue = 8 | pages = 2223–30 | year = 1999 | pmid = 10221307 }}</ref><ref name="McClatchey2002">{{cite book|last=McClatchey|first=Kenneth D.|title=Clinical laboratory medicine|url=https://books.google.com/books?id=3PJVLH1NmQAC&pg=PA288|year=2002|publisher=Lippincott Williams & Wilkins|isbn=978-0-683-30751-1|page=288}}</ref><ref name="MengelSchwiebert2005">{{cite book|last1=Mengel|first1=Mark B.|last2=Schwiebert|first2=L. Peter|title=Family medicine: ambulatory care & prevention|url=https://books.google.com/books?id=XvLo7xvmFo0C&pg=PA268|year=2005|publisher=McGraw-Hill Professional|isbn=978-0-07-142322-9|page=268}}</ref> Most [[liver disease]]s cause only mild symptoms initially, but these diseases must be detected early. Hepatic (liver) involvement in some diseases can be of crucial importance. This testing is performed on a patient's blood sample. Some tests are associated with functionality (e.g., albumin), some with cellular integrity (e.g., [[transaminase]]), and some with conditions linked to the biliary tract ([[gamma-glutamyl transferase]] and [[alkaline phosphatase]]). Because some of these tests do not measure function, it is more accurate to call these liver chemistries or liver tests rather than liver function tests.<ref>{{Cite journal|last1=Kwo|first1=Paul Y.|last2=Cohen|first2=Stanley M.|last3=Lim|first3=Joseph K.|date=January 2017|title=ACG Clinical Guideline: Evaluation of Abnormal Liver Chemistries|url=https://dx.doi.org/10.1038%2Fajg.2016.517|journal= American Journal of Gastroenterology|language=en-US|volume=112|issue=1|pages=18–35|doi=10.1038/ajg.2016.517|pmid=27995906|s2cid=23788795|issn=0002-9270}}</ref> Several biochemical tests are useful in the evaluation and management of patients with hepatic dysfunction. These tests can be used to detect the presence of liver disease. They can help distinguish among different types of liver disorders, gauge the extent of known liver damage, and monitor the response to treatment. Some or all of these measurements are also carried out (usually about twice a year for routine cases) on individuals taking certain medications, such as anticonvulsants, to ensure that these medications are not adversely impacting the person's liver.{{cn|date=May 2022}}

==Standard liver panel==

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| 7-56 IU/L<ref name="Shivaraj 2009"/>

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Apart from being found in high concentrations in the liver, ALT is found in the kidneys, heart, and muscles. It catalyses the [[transamination]] reaction, and only exists in a cytoplasmic form. Any kind of liver injury can cause a rise in ALT. A rise of up to 300 IU/L is not specific to the liver, but can be due to the damage of other organs such as the kidneys or muscles. When ALT rises to more than 500 IU/L, causes are usually from the liver. It can be due to hepatitis, ischemic liver injury, and toxins that causes liver damage. The ALT levels in [[Hepatitishepatitis C]] rises more than in Hepatitishepatitis A and B. Persistent ALT elevation more than 6 months is known as [[chronic hepatitis]]. [[Alcoholic liver disease]], [[Nonnon-alcoholic fatty liver disease]] (NAFLD), fat accumulation in liver during childhood obesity, [[steatohepatitis]] (inflammation of fatty liver disease) are associated with a rise in ALT. Rise in ALT is also associated with reduced insulin response, reduced glucose tolerance, and increased free [[fatty acid]]s and [[triglyceride]]s. Bright liver syndrome (bright liver on ultrasound suggestive of fatty liver) with raised ALT is suggestive of [[metabolic syndrome]].<ref name="Shivaraj 2009"/>

In pregnancy, ALT levels would rise during the second trimester. In one of the studies, measured ALT levels in pregnancy-related conditions such as [[hyperemesis gravidarum]] was 103.5 IU/L, [[pre-eclampsia]] was 115, [[HELLP syndrome]] was 149. ALT levels would reduce by greater than 50% in three days after child delivery. Another study also shows that [[caffeine]] consumption can reduce the risk of ALT elevation in those who consume alcohol, overweight people, impaired glucose metabolism, and viral hepatitis.<ref name="Shivaraj 2009"/>

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| 3.5 to 5.3 g/dL

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[[Albumin]] is a protein made specifically by the liver, and can be measured cheaply and easily. It is the main constituent of total protein (the remaining constituents are primarily [[globulins]]). Albumin levels are decreased in chronic liver disease, such as [[cirrhosis]]. It is also decreased in [[nephrotic syndrome]], where it is lost through the urine. The consequence of low albumin can be edema since the intravascular [[oncotic pressure]] becomes lower than the extravascular space. An alternative to albumin measurement is prealbumin, which is better at detecting acute changes (half-life of albumin and prealbumin is about 2 weeks and about 2 days, respectively).<ref>{{Cite journal|last=Smith|first=Susan H.|date=April 2017|title=Using albumin and prealbumin to assess nutritional status|url=https://dx.doi.org/10.1097%2F01.NURSE.0000511805.83334.df|journal=Nursing2021|language=en-US|volume=47|issue=4|pages=65–66|doi=10.1097/01.NURSE.0000511805.83334.df|pmid=28328780|issn=0360-4039}}</ref><ref>{{Cite web|title=Prealbumin Blood Test: MedlinePlus Medical Test|url=https://medlineplus.gov/lab-tests/prealbumin-blood-test/|access-date=2021-02-25|website=medlineplus.gov|language=en}}</ref>

== Other tests ==

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Ceruloplasmin is an [[acute phase protein]] synthesized in the liver. It is the carrier of the copper ion. Its level is increased in infections, [[rheumatoid arthritis]], pregnancy, non-Wilson liver disease and obstructive jaundice. In Wilson disease, the ceruloplasmin level is depressed which lead to copper accumulation in body tissues.<ref name="Shivaraj 2009"/>

===Alpha-fetoprotein (AFP)===

{| class="wikitable" align="right"

| Reference range

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{{Main|Alpha-fetoprotein}}

Alpha-fetoprotein (AFP) is significantly expressed in foetal liver. However, the mechanism that led to the suppression of AFP synthesis in adults is not fully known. Exposure of the liver to cancer-causing agents and arrest of liver maturation in childhood can lead to the rise in AFP. AFP can reach until 400–500 μg/L in [[hepatocellular carcinoma]]. AFP concentration of more than 400 μg/L is associated with greater tumour size, involvement of both lobes of liver, portal vein invasion and a lower median survival rate.<ref name="Shivaraj 2009"/>

===Coagulation test===

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===Urea===

↑UreaElevated =urea may indicate acute or chronic kidney disease, urinary tract obstruction, congestive heart failure, recent MI,myocardial Infarction or gastrointestinal bleeding.{{cn|date=November 2021}}

==See also==