What is the purpose of conducting a Liver Function Test (LFT)?

Liver function tests (LFT’s) are set of investigations used to monitor the functions of the liver or to help diagnose and monitor derangements in diseases directly or indirectly affecting the liver.  The usual tests done under the LFT’s include, serum bilirubin (Total,direct and indirect), Serum proteins (Albumin and Globulins) and liver enzymes (Alanine transaminase, Aspartate transaminase, Alkaline phosphatase and Gamma glutamyl transpepdidase). 

The clinician usually asks for the LFT’s when he encounters signs and symptoms indicative of stress on the liver. The usual signs include Malaise, Weakness, body aches, abdominal discomfort, altered bowel habits among others. A “YELLOW EYE” is usually a tell tale sign of liver damage where bilirubin is elevated and in these cases LFT’s give a treasure of information to the treating physician. 

Bilirubin and its derivatives are usually elevated in liver diseases like infective hepatits. It is worthwhile to note that Bilirubin can also be elevated in hematological derangements affecting the red blood cells, which are usually referred to as the hemolytic anemias which affect  toddlers  and adults in various clinical scenarios. Bilirubin elevation, predominantly the direct fraction, is noted in patients with Gall stones or due to obstructions to the flow of bile affecting the gall bladder, Pancreas and sometimes the liver also. 

Liver enzyme tests as mentioned above, give a hint to the metabolic function of the liver. ALT is considered the specific test for liver cell injury. AST is somewhat non-specific and can be deranged in disorders of muscle. However a ALT: AST ratio of more than 2 is usually indicative of Alcoholic liver disease. An increase in Alkaline phosphatase is indicative of cholestasis.  Combined increase in Gamma GT and ALP is useful to confirm hepatic origin of diseases and drug Induced changes. 

Serum Albumin, Globulin and Prothrombin time are useful to assess the synthetic function of the liver. Reduced Albumin is indicative of various disorders including those affecting the kidney. Increase globulins are noted in infections, inflammatory disorders and few drug induced side effects.

The brief explanation of LFT’s gives information to the treating physician to whether he is dealing with a cholestatic (obstructive) pattern or hepatocellular damage or sometimes both. LFT’s are hence important to guide the physician in instituting right therapy and guide the patient on further course of action.  Abnormal LFT’reports are relatively common and most people with these results have normal liver function. An infection or a reaction to food or drug might affect your blood report and sometimes a subsequent liver blood test after a nterval of 3 weeks is all that’s needed to allay unwanted fears. Your family doctor has then the liberty to ask for ancillary tests to pinpoint the abnormalities after evaluating a LFT. These may include radiological methods like ultrasound, CT or MRI scans, which help doctors get a better picture of the extent of any damage to the liver. In certain cases a liver biopsy may be considered to specifically diagnose a condition or provide information on the extent of  liver damage.

If you are very unwell, you may be referred or admitted to hospital, although this is unusual – only a very small number of people with abnormal liver blood tests require admission.

In conclusion, Liver Function Tests (LFT’s) play a vital role in diagnosing and monitoring liver health. They encompass various components, shedding light on liver function, which can be affected by a range of conditions. Notably, LFT test prices in India vary, but on average, they fall between Rs 400 to Rs 1,000. Regular LFTs aid in early detection and informed treatment decisions, helping patients maintain liver health. Abnormal results are relatively common, but further tests and medical guidance can clarify any concerns. Hospitalization is rarely needed for individuals with abnormal liver blood test results.