Home Biomarkers HAV AB IgM

HAV AB IgM

Hepatitis Biomarker

Sample Needed

Collection Type: Blood

Body System

Related System: Hepatitis

Overview

HAV Ab IgM is an immunoglobulin M antibody produced by the immune system in response to infection with hepatitis A virus (HAV). The test detects recent or acute HAV infection by measuring IgM-class antibodies directed against HAV. A positive IgM indicates current or very recent infection, while IgG (not measured here) indicates past infection or immunity. This test is used when patients have symptoms such as jaundice, dark urine, pale stools, fatigue, nausea, abdominal pain, or fever, or after known exposure or travel to areas with poor sanitation. Children often have milder or asymptomatic infections but can still test IgM-positive; older adults more often have symptomatic disease. Immune status (e.g., immunosuppression) can affect antibody production and timing.

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Test Preparation

Clinical history is preferred

Why Do I Need This Test

Profile: Hepatitis panel / Hepatitis A testing - Symptoms: Jaundice, anorexia, nausea, abdominal pain, dark urine, fever, fatigue or after exposure/travel - Diagnoses/monitoring: Confirms acute/recent HAV infection and helps guide public-health measures - Abnormal levels: Positive IgM indicates recent infection; false positives/negatives can occur - Biological meaning: IgM shows active/recent immune response to HAV - Behaviors/lifestyle: Recent travel to endemic areas, consumption of contaminated food/water, close contact with an infected person - Family history/contacts: Household or close-contact exposure to a confirmed HAV case warrants testing

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Symptom Checker

Understanding Test Results

Index <1.0 (Negative/non-reactive): No evidence of recent HAV infection.
Person may be susceptible (if IgG not present) or previously vaccinated (check IgG or vaccination history).
Equivocal/borderline (commonly 0.8–1.2 or lab-dependent): Indeterminate repeat testing in 1–2 weeks and/or check HAV IgG or PCR for clarification.
Index ≥1.0–1.1 (Reactive/positive depending on assay): Consistent with acute or recent HAV infection.
IgM typically becomes detectable around the time of symptom onset (often within 5–10 days), peaks in the first few weeks, and usually persists for about 3–6 months.
A positive result should prompt clinical correlation, testing of household/close contacts, and public-health measures.
False positives: May occur in low-prevalence settings or with cross-reacting antibodies (other infections, autoimmune conditions); confirm with clinical picture and additional testing.
False negatives: Possible early in infection (window period) or in immunocompromised patients who do not mount a strong IgM response; consider repeat testing or HAV RNA testing if suspicion remains high.

Normal Range

Negative Non‑reactive Index <1.0 (S/CO)

FAQs

Q: What is HAV ab IgM?

A: HAV ab IgM is the immunoglobulin M antibody produced in response to hepatitis A virus infection. Its presence in blood indicates acute or recent infection, usually detectable within 1–3 weeks after exposure and persisting for a few months. Testing helps diagnose recent cases and guide public-health steps; results should be interpreted with clinical findings and may be followed by HAV IgG testing for immunity.

Q: Is HAV infection serious?

A: Hepatitis A infection is usually acute and self-limiting, causing fatigue, jaundice, nausea and abdominal pain that resolve in weeks to months. It does not cause chronic liver disease, but can be more severe in older adults or people with pre-existing liver conditions and rarely leads to fulminant liver failure requiring hospitalization. Vaccination and good hygiene effectively prevent infection.

Q: What if hepatitis A IgM is positive?

A: A positive hepatitis A IgM indicates an acute or recent hepatitis A infection and that the person may be contagious. Prompt medical assessment is needed, with liver function tests and supportive care (rest, fluids, avoid alcohol and hepatotoxic drugs). Notify public health; close contacts may need hepatitis A vaccine or immunoglobulin. Practice strict hand hygiene and avoid food handling until cleared.

Q: What happens if you test positive for hepatitis A?

A: If you test positive for Hepatitis A, you'll usually get supportive care: rest, hydration, symptom control, and avoid alcohol or hepatotoxic drugs. Hepatitis A is often self-limited but can rarely cause severe liver problems in older people or those with chronic liver disease. Public health is notified for contact tracing; close contacts may receive vaccine or immune globulin. Good hand hygiene prevents spread.

Q: What does positive HAV mean?

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Q: Can HAV IgM levels return to normal without treatment?

A: Yes. Hepatitis A IgM antibodies usually rise during acute infection and then fall to undetectable levels as the illness resolves, often within 3 to 6 months without specific antiviral treatment because hepatitis A is typically self-limited. IgG then provides long-term immunity. Occasionally IgM may persist longer; persistent or atypical courses warrant medical follow-up and testing.