• Published on: Sep 15, 2021
  • 5 minute read
  • By: Dr Rakesh Rai

Everything About Liver Function Tests- Purpose & Significance

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Everything About Liver Function Tests- Purpose & Significance

Liver function tests are medical laboratory tests that measure the number of various substances in the blood that are released into your blood by liver cells or made by your liver. These substances are often called "liver enzymes" because they are enzymes that are produced exclusively by the liver to help regulate metabolism for processing chemicals, nutrients, and drugs.

A high level of any one of these may suggest an abnormal situation involving your liver. The most common symptoms associated with a problem involving your liver include nausea, vomiting, yellowing skin color (jaundice), fever, and abdominal discomfort such as pain on gentle pressing around about halfway down on the right side of the abdomen.

A liver function test is a blood test that evaluates an individual's liver function or sees if there may be a problem in this organ. Liver functions including leukocyte count, alkaline phosphatase, ALT/AST enzymes, and bilirubin levels are measured with results interpreted by physicians who then advise treatment options to relieve pain or reduce the risk of liver disease. If the level of these agents is elevated then the physician will typically recommend further diagnostics such as antibody testing for hepatitis B and C infections, ultrasounds, and biopsies.

Liver function tests are a series of blood tests used to evaluate liver function. Tests may include the following:

  • Inclusion of serum albumin or total proteins as variables in the SMA12 test
  • Albumin fractional catabolic rate (ACR) and erythrocyte sedimentation rate (ESR) measurements, which can be used as a surrogate marker for changes in hepatocellular activity
  • Visible change is indicative that hepatocytes have been damaged or destroyed, an indicator that liver disease is present.
  • Fractional synthetic rate of albumin synthesis calculated from measurements of serum creatinine and urinary urea nitrogen providing information about hepatocyte intracellular mass status with decreased album

The most common of these are aminotransferases ALT and AST. These enzymes are released into the bloodstream in excessive amounts by the cells that line the bile ducts that carry bile from the liver - where it gets made - to where it gets used up in digestion ??i.e., all over your body, not just in your liver but also near your kidneys) when there's any sort of problem with those cells or with damage done to them because of some other hurtful event.

In the context of a medical lab test, a liver function test is anyone that has to do with the liver. Serum bilirubin, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase are common ones. A veterinarian could use ultrasound as well as biochemistry analysis. These tests show how well your liver is performing its duty to remove toxins from your body and to make bile for those toxins.  Liver function tests are conducted to assess the liver's ability to convert inactive substances in your blood to active ones.

Alanine aminotransferase (ALT/SGPT): tests what process - amino acid, carbohydrate, or fat - your liver is having trouble breaking down to store sugar for later use indigestion. This test will only show what type of enzyme the liver has difficulty processing at this time, so if this is normal but an alkaline phosphatase test comes back abnormal, this means there may be a different illness affecting the liver.

The test can measure certain chemicals that are released because of metabolism and excreted from the body in urine, such as albumin.

The most common indicators measured by blood-based liver function tests include GGT, ALP, total bilirubin / conjugated/unconjugated bilirubin, ALT and ASAT.

A group of enzymes found in healthy livers called GOT (gamma-glutamyl transpeptidase) and GPT (gamma-glutamyltransferase) can also be measured to determine damage to liver cells.

Liver Function Tests (LFTs) are a group of tests that measure the levels and function of various substances in the blood leave before digestion and within the liver. These include enzymes and proteins made by the liver; cholesterol, copper, iron, calcium, sodium, potassium; bilirubin level; albumin levels. The LFTs can be used to help diagnose many diseases such as viral hepatitis or alcoholic liver disease.

A history would normally prompt additional testing such as abdominal imaging for gallstones or metabolic abnormalities like cirrhosis caused by alcohol consumption. Kidney function should be tested because high-protein diets may cause kidney problems too. A genetic test might be warranted if there is a family history of inheritance. Liver function tests are a group of blood tests that doctors might use to evaluate the liver's ability to gather and store glycogen (sugar) and protein, produce bile, filter the blood, and produce cholesterol.

Drugs can accumulate in liver cells, leading to changes in levels of enzymes. Enzymes that are elevated may indicate an inflammatory or viral process as well as the use of certain medications such as steroids which need some time to clear from the body after discontinuation. The test isn't specific for any disease but can show if there is a liver problem even before symptoms occur, including cirrhosis and early hepatitis B and C infections. When first conducted, rapid elevations or decreases might be indications of acute injury or pre-clinically chronic injury respectively.

The liver may be the body's most important gland. It synthesizes nutrients from fat, carbohydrates, and protein into a form that can be absorbed by the blood to supply the cells, brain, and other tissues with a continuous supply of fuel. The liver also acts as a storage center for high-density energy reserves in times of food shortage or famine.

In response to viruses or bacteria which enter from our gut through their ingestion of contaminated water or insects’ excretions for example), substances called antibodies are manufactured in great numbers by specialized cells in an inflammatory reaction known as acute hepatitis. LFT helps measure the liver's endurance, by testing erythrocyte count, serum albumin level, bilirubin level and prothrombin time.

It's normal for your erythrocyte count to drop over time as you age. This is due mainly to the production of fewer red blood cells in your bone marrow. It may provide an indication of what is happening inside the liver with regard to the regeneration of new cells. An elevated or persistently high level can indicate cirrhosis or cancer. If it's persistently high, then requires radiologic imaging for diagnosis.

The liver function tests are blood tests that tell the physician how well the liver is working. The enzymes GGT, ALT, AST, and ALP are primarily tested to examine what should be healthy activities through three phases of hepatic metabolism. Since these enzymes exist primarily in the liver, they do not normally show up in any other tissue or fluid other than the bloodstream. If there is a disease that affects the cells within the liver, then inflammatory processes will ensue. This will lead to excessive production of oxygen-free radicals to facilitate cell death and release toxins into circulation which can affect all body systems including altering enzyme quantities, so they bump up against their normal reference ranges for evaluation.

The purpose of liver function tests is to diagnose and monitor a person's condition, based on levels of certain enzymes in the blood.

A high level of transaminases might be due to a variety of diseases or conditions, including hepatitis, cirrhosis, biliary obstruction from gallstones, or pancreatitis. Liver disease disrupting the production and release of albumin will also produce abnormally low-level albumin which can be detected with this test. A qualitative determination can be made if large amounts of Clotting Factor VIII are released into the bloodstream - Hepaetous Patina (HP) - leading to severe bleeding episodes independent from coagulation defects where plasma clotting normally should take place.

Liver function tests measure the level of different substances produced or used by the liver, such as albumin. The liver conditions may include fatty liver (hepatic steatosis), alcoholic hepatitis, cirrhosis, and many disorders affecting other parts of the body which ultimately damage the working capacity of your liver. Liver function tests are not meant to detect acute hepatitis or mild cases of elevated enzyme levels that commonly resolve on their own. Normal results suggest that there is no abnormality with your kidneys. Abnormal livers often show high amounts of creatinine kinase (CK) and alanine aminotransferase (ALT).

The liver is the body's only organ able to break down toxic compounds, so its function must be checked. The example you gave -- SGPT, or aspartate aminotransferase -- measures the level of a major liver enzyme. High levels could indicate damage from drugs also used for weight loss, such as acetaminophen/paracetamol (Tylenol) or metformin (Glucophage). Too-low levels of hepatocyte enzymes mean that the liver's not functioning properly and may develop complications like hepatitis and cirrhosis.

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Asthma

Asthma Symptoms in Adults: Early Signs, Triggers, and When to Seek Care

Asthma is often perceived as a childhood condition, but a significant number of cases develop or persist into adulthood. In India, adult asthma is increasingly recognised due to rising air pollution, occupational exposure and lifestyle-related risk factors. Unfortunately, asthma symptoms in adults are frequently misdiagnosed as recurrent infections, allergies or age-related breathlessness, leading to delayed treatment.

Understanding adult asthma symptoms is critical for early diagnosis, effective control and prevention of severe attacks.

 

What Is Asthma?

Asthma is a chronic inflammatory disease of the airways. In asthma, the airways become:

  • inflamed
     

  • narrow
     

  • overly sensitive to triggers
     

This leads to difficulty in breathing, especially during exposure to specific stimuli.

 

Why Adult Asthma Is Often Missed

Adult asthma symptoms may:

  • appear gradually
     

  • vary in severity
     

  • mimic common respiratory conditions
     

According to Indian Council of Medical Research and WHO data, many adults remain undiagnosed for years, increasing the risk of complications.

 

Common Asthma Symptoms in Adults

Wheezing

A high-pitched whistling sound while breathing, especially during exhalation, is a classic asthma sign.

 

Shortness of Breath

Adults with asthma often feel:

  • breathless during routine activities
     

  • difficulty taking deep breaths
     

This may worsen at night or early morning.

 

Chest Tightness

Many describe a sensation of pressure or tightness in the chest, which can be mistaken for heart-related issues.

 

Chronic Cough

A persistent cough, especially:

  • at night
     

  • early morning
     

  • after exercise
     

is a common but overlooked asthma symptom.

 

Symptoms That Worsen With Triggers

Asthma symptoms often intensify after exposure to specific triggers.

Air Pollution and Smoke

Urban pollution, vehicle emissions and indoor smoke significantly worsen asthma symptoms in adults.

 

Allergens

Dust mites, pollen, mould and pet dander are common triggers.

 

Respiratory Infections

Viral infections can trigger asthma flare-ups or reveal undiagnosed asthma.

 

Physical Activity

Exercise-induced asthma causes breathlessness and wheezing during or after physical exertion.

 

Weather Changes

Cold air, humidity and sudden temperature changes can aggravate symptoms.

 

Adult-Onset Asthma

Adult-onset asthma differs from childhood asthma.

Characteristics include:

  • onset after age 20–30
     

  • less association with childhood allergies
     

  • more persistent symptoms
     

  • higher likelihood of severe disease
     

Occupational exposure and hormonal changes contribute to adult-onset asthma.

 

Risk Factors for Asthma in Adults

Several factors increase asthma risk:

  • long-term exposure to pollution
     

  • smoking or passive smoking
     

  • occupational chemicals or dust
     

  • obesity
     

  • family history of asthma
     

  • chronic sinusitis or allergies
     

Women may experience asthma onset or worsening during hormonal changes.

 

When Asthma Symptoms Become Serious

Seek immediate medical attention if experiencing:

  • severe breathlessness
     

  • difficulty speaking in full sentences
     

  • bluish lips or fingertips
     

  • rapid worsening of symptoms
     

  • poor response to usual inhalers
     

These signs indicate a potentially life-threatening asthma attack.

 

How Adult Asthma Is Diagnosed

Diagnosis includes:

  • detailed symptom history
     

  • physical examination
     

  • lung function tests (spirometry)
     

  • response to bronchodilators
     

Early diagnosis improves long-term outcomes.

 

Impact of Untreated Asthma

Untreated asthma can lead to:

  • frequent attacks
     

  • reduced lung function
     

  • sleep disturbances
     

  • missed workdays
     

  • reduced quality of life
     

According to Lancet respiratory studies, uncontrolled asthma increases hospitalisation risk.

 

Managing Asthma Symptoms in Adults

Effective asthma management focuses on:

  • identifying and avoiding triggers
     

  • using prescribed inhalers correctly
     

  • monitoring symptoms regularly
     

  • maintaining follow-up care
     

Asthma action plans help patients recognise worsening symptoms early.

 

Role of Preventive Healthcare

Preventive healthcare helps:

  • detect asthma early
     

  • assess lung function
     

  • guide lifestyle modifications
     

Regular health checkups are especially important for individuals with respiratory symptoms or occupational exposure.

 

Lifestyle Measures That Support Asthma Control

Helpful practices include:

  • avoiding smoking
     

  • improving indoor air quality
     

  • wearing masks in polluted environments
     

  • maintaining healthy weight
     

  • regular, moderate exercise
     

Lifestyle support complements medical treatment.

 

Mental Health and Asthma

Stress and anxiety can worsen asthma symptoms.

Stress management:

  • reduces symptom frequency
     

  • improves medication response
     

Holistic care improves asthma outcomes.

 

Importance of Medication Adherence

Asthma medications work best when:

  • taken regularly as prescribed
     

  • inhaler technique is correct
     

Skipping treatment increases flare-up risk.

 

Long-Term Outlook for Adults With Asthma

With proper management:

  • symptoms are well controlled
     

  • severe attacks are preventable
     

  • normal activity levels are achievable
     

Most adults with asthma lead active, productive lives.

 

Conclusion

Asthma symptoms in adults are often subtle, variable and easily mistaken for common respiratory problems. Wheezing, breathlessness, chest tightness and chronic cough should not be ignored, especially when triggered by pollution, exercise or weather changes. Early diagnosis, trigger control and consistent treatment are essential to prevent severe attacks and preserve lung health. Recognising adult asthma early empowers individuals to manage symptoms effectively and maintain a good quality of life.

 

References

  • Indian Council of Medical Research (ICMR) – Respiratory Disease and Asthma Studies
  • World Health Organization (WHO) – Asthma Management and Prevention Guidelines
  • National Family Health Survey (NFHS-5) – Respiratory Health Indicators
  • Lancet Respiratory Medicine – Adult Asthma Outcomes and Management
  • NITI Aayog – Air Pollution and Respiratory Health Reports
  • Statista – Global Asthma Prevalence and Trends

See all

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