Description of the blood test: 

The Human Herpesvirus 6 (HHV-6) IgG antibody test is a serological investigation used to determine whether a person has been previously infected with HHV-6. This virus is extremely common and, after the initial infection, remains latent in the body for life. The presence of IgG antibodies indicates a past infection and the development of long-term immunological memory. In healthy individuals, these antibodies remain stable, but their levels are monitored in immunocompromised patients to detect potential viral reactivation.

What does the analysis represent?

• Purpose: Determination of the immune status and presence of long-term antibodies to Human Herpesvirus type 6.
• Primary application: Confirmation of past exposure, assessment of immunity, and monitoring of high-risk patients (e.g., transplant recipients).
• Performance: High-precision immunoassay of a venous blood sample.

Recommendations for the test (General)

• Time: Blood collection is recommended during the morning hours.
• Fasting: A food intake pause of 4–8 hours is preferred.
• Rest: Spend 15–30 minutes in a calm state before the blood draw.
• Important: A single IgG test indicates previous exposure but does not determine the exact timing of the primary infection.

What can affect the results?

• Immunosuppression: Patients with weakened immune systems may show lower or delayed antibody levels.
• Cross-reactivity: Other viruses in the herpes family (such as HHV-7 or CMV) can sometimes cause minor interference in the assay.
• Infant Testing: Presence of maternal IgG antibodies in children under 12 months may lead to a positive result.
• Recent Transfusions: Blood or immunoglobulin therapy within the last few months can introduce donor antibodies.

When to take the test?

• Recommendations: Prescribed for patients with chronic fatigue symptoms, fever of unknown origin, or as part of a screening before organ or bone marrow transplantation.
• Preparation: Standard preparation for serological tests; avoid heavy meals and alcohol 24 hours prior to the analysis.

How to interpret the results?

The interpretation of laboratory data is the exclusive responsibility of a qualified physician. A detected level of HHV-6 IgG is a biochemical indicator of the body’s past encounter with the virus and is not a standalone diagnosis of a current illness. The physician must analyze this marker alongside clinical symptoms, the patient’s immune status, and potentially other tests (like PCR or IgM). Only an expert can determine if the virus is in a latent state or if there are signs of reactivation requiring clinical management.

Possible further investigations

• HHV6 IgM Ab: To check for a current or very recent active infection.
• HHV6 DNA (PCR): To detect active viral replication in the blood or tissues.
• Complete Blood Count (CBC): To check for characteristic changes in white blood cell levels.
• Consultation with an Infectious Disease Specialist: To determine the clinical significance of the viral status.

When does the next step make sense?

Understanding your HHV-6 status is important if you are experiencing persistent symptoms or are preparing for significant medical procedures. The next step is a professional medical review to clarify the status of the virus and ensure appropriate monitoring, especially for individuals with weakened immune systems.

👉 If necessary, you can discuss the test results with our specialized — immunologist (Doctors – TAMC).