Anti hepatitis E virus (Anti HEV) IgM Test

What is the Anti HEV IgM test?

The hepatitis E virus (HEV) targets the liver causing inflammation and cell damage. As per estimates by WHO, around 20 million people are affected by the virus annually throughout the world. A significant percentage of those figures lead to the death of the patient. While most people can recover from an attack of the virus, it can be specifically dangerous for pregnant women and patients with weak immune systems.

This also includes the elderly or people who are seriously ill.
The disease is primarily waterborne and is most common in the eastern and southern regions of Asia.  On the whole, the virus is considered as a major public health problem in many developing countries and an emerging health threat in multiple developed countries.

The virus has four different genotypes which are marked as 1, 2, 3 and 4. The first two are found in humans while the remaining two circulate in animals, without causing any disease. In general, genotype 1 is found in parts of Asia and Africa, genotype 2 in Mexico and West Africa and genotype 4 in Taiwan and China. 

In some cases, the HEV genotypes 3 and 4 have been extracted from pork, boar, and deer meat which suggests the possibilities of foodborne infection, especially when the food is not properly cooked. The exact period of infection of the virus has not yet been determined.

The test determines the level of the IgM antibodies in the blood, produced in response to an infection. The disease is often underdiagnosed and it results in cirrhosis in organ transplant recipients, patients undergoing chemotherapy and individuals with HIV infection. The virus is also responsible for various other disorders including a range of neurological syndromes, renal injury, pancreatitis, and various hematological problems.

The neurological manifestations include ailments like Guillain-Barré syndrome, Bell’s palsy, neuralgic amyotrophy, acute transverse myelitis, and acute meningoencephalitis. HEV1 infections are also associated with acute pancreatitis. Cases of stillbirth and excess mortality are also observed in pregnant women due to obstetric problems, including hemorrhage, eclampsia or hepatic failure.

The disease is more common in those parts of the world with poor handwashing habits and lack of clean water. Transmission can also occur can occur through contaminated food and water, blood transfusions and through mother-to-child transmission. In a small portion of the patients, the virus can lead to acute hepatitis failure which is associated with a high mortality rate if intensive care support and liver transplantation are not available.

The anti-HEV IgM antibody in serum is formed after an incubation period which ranges from 15 to 60 days. This is followed by the detectable levels of anti-HEV IgG within the next few days. The anti-HEV IgM levels are detectable for up to six months from the onset of the symptoms. In most cases, the initial positive results are followed by confirmatory testing which may include detection of HEV RNA in serum or stool.
 

Why do I need to undergo an anti-HEV IgM test?

The test is conducted when the doctor inspects the symptoms and suspects an HEV infection. The symptoms of an infection can include the following.

– Fever
– Fatigue
– Loss of appetite
– Nausea and vomiting
– Abdominal pain specifically on the right side of the belly
– Jaundice
– Dark urine
– Clay-colored stool
– Joint pain
– Skin rash or itching
– A slightly enlarged and tender liver termed as hepatomegaly.

The physician also examines the medical history of the patient and recent travel records to inspect for any chances of an infection.

How is an Anti-HEV IgM test performed?

For the IgM antibody testing, a blood sample is drawn from a vein through a needle and the process is termed as venipuncture. The process very simple and it involves the following steps.

– The collection area is initially disinfected to prevent any infections.

– The collection site is generally around the elbow region but at times it can also be at the back of the hand.

– An elastic band is tied in the upper arm to make the vein swell with blood, thus making them more visible and the collection process easier.

– A needle is inserted into the vein and the required volume of blood is drawn through it in an attached vial. Slight pain or a stinging sensation is felt when the needle is inserted.

– The band is loosened to release the pressure on the arm and the needle is gently withdrawn. Some pressure is applied on the site through a gauze or a cotton role to prevent any excess bleeding. The spot is then covered with a sterile bandage and the sample is sent to the laboratory for testing.

– The entire process is safe and is generally concluded within a few minutes. Since the size of the veins varies from one person to the other, locating the right vein may be difficult for some patients and multiple punctures may be needed.

– For infants or young children, veins are difficult to find and hence, a sharp tool called a lancet is often used to break the skin and collect the required volume of blood.  

– In some cases, a patient might feel dizzy or lightheaded due to loss of blood after the collection and may need proper care. The puncture site might develop a bruise or get painful, which is normal and usually gets fixed within a few days.

– In some exceptional cases, there might be excessive bleeding or the puncture site can develop an infection.

What is the price for an Anti-HEV IgM test? 

The cost of the test varies between Rs 600 to Rs 2500 depending on the location and facilities provided in the testing center.

When will I get the test results?

The test results are usually delivered within 24 to 48 hours, depending on the laboratory.

What is the normal range for an Anti-HEV IgM test?

The test results are either negative, positive or intermediate, based on the presence or absence of the IgM antibody in the blood.

What do the results mean?

The positive results confirm the presence of acute or recent hepatitis E infection while the negative results indicate the absence of the virus. The intermediate results can be interpreted in the following manner.

– Acute hepatitis E infection with a rising level of anti-hepatitis E virus (HEV) IgM

– A recent hepatitis E infection with a declining level of anti-HEV IgM.

– An acute hepatitis E infection due to HEV genotype 2 strains.

– Cross-reactivity with nonspecific antibodies resulting in a false-positive result.

– A negative result in a patient with the right symptoms does not indicate the absence of a recent hepatitis E infection.

In such cases, the test is often repeated within 2 weeks.

Do I need to fast for the Anti-HEV IgM test?

Fasting is not necessary before appearing for the test.

What else do I need to know before I appear for an anti-HEV IgM test?

The following points highlight some of the aspects of the test for a clearer insight.

For healthy patients with normal immune systems, medications may not be needed for a hepatitis E infection as it is a self-limited infection.

The doctor may advise the patient to take sufficient rest, eat healthy foods, drink plenty of fluids, avoid alcohol and practice good hygiene until the infection runs its course and gets removed from the system.

Pregnant women, individuals with weak immune systems or people with acute liver failure will likely be hospitalized and carefully monitored.

The diagnosis of the disease is challenging because distinguishing between different forms of hepatitis is difficult. Multiple tests may be needed for an accurate diagnosis.

Prevention is considered as the most effective approach against the disease. The right sources of drinking water and the correct methods of disposal of human wastes are the primary requirements to prevent it from spreading. It is also necessary to avoid uncooked and unpeeled foods.

Can pregnant women undergo an Anti-HEV IgM test?

Pregnant women can undergo the test without any restrictions.

Is an Anti HEV IgM test possible for new-born babies?

The test can be conducted on new-born babies as advised by the doctor.