Guide for patients: how to interpret your hepatitis B and C serology results

We often have blood tests done and find ourselves faced with results that seem full of incomprehensible codes and acronyms. What do these results really mean for our health? Understanding them is crucial for making the right decisions and protecting ourselves. At Ambar Lab, we will explain in simple terms how to interpret hepatitis B and C serology results and what implications they may have for your well-being.

What is hepatitis serology?

When we talk about serology, we are referring to blood tests that detect antibodies (defences generated by your immune system) and antigens (proteins from the virus itself). In the case of hepatitis B and C, these tests provide information to determine whether you have been in contact with the virus, whether the infection is active, or whether you are already protected. Hepatitis B and C serology is based on this logic:

• Antigens indicate the presence of the virus.
  
• Antibodies indicate the body’s response to that virus, either through previous infection or vaccination (in the case of hepatitis B).

Differences between hepatitis B and hepatitis C tests

Although both are viral hepatitis, the serological markers are not the same:

• Hepatitis B (VHB):
  
  • Antigens such as HBsAg and HBeAg are analysed, as well as antibodies such as anti-HBs, anti-HBc (total or IgM) and anti-HBe.
    
  • The combination of these markers allows us to determine whether the infection is acute or chronic, and whether you are immunised through vaccination or because you have already had the infection.
    
• Hepatitis C (VHC):
  
  • First, the presence of anti-HCV antibodies is sought.
    
  • Next, to confirm if there is an active infection, the HCV RNA (viral load) is analyzed using molecular biology techniques.
    

Key components of hepatitis B serology

In hepatitis B and C serology, the hepatitis B panel usually includes several markers that are read together:

HBsAg: hepatitis B surface antigen

It is a protein that coats the virus.

• HBsAg positive: indicates that the hepatitis B virus is present. This may be an acute or chronic infection, depending on the context and duration of positivity.
  
• Negative HBsAg: suggests that there is no active infection, but it will be necessary to look at the other markers to determine whether the person is susceptible, immunised, or has had the infection.
  

Detection of HBsAg is the basis for diagnosing HBV infection in clinical guidelines.

Anti-HBs: antibodies that indicate protection

These are antibodies directed against the surface antigen. Their presence is usually interpreted as protection against the B virus:

• Anti-HBs positive (≥ 10 mIU/ml) and HBsAg negative: this is considered a protective level, either due to vaccination or having naturally overcome the infection.
  
• Negative anti-HBs: indicates no protection; if there are no other markers either, the person is susceptible to infection.
  

In vaccinated individuals, the goal is to achieve a sufficient level of anti-HBs to ensure lasting immunity.

Anti-HBc: evidence of contact with the virus

Shows that there has been contact with the virus at some point in life:

• Positive total anti-HBc: indicates past or current hepatitis B infection.
  
• IgM anti-HBc positiva: asociada a infección aguda o reactivación reciente.
  

In some cases, a pattern called ‘isolated anti-HBc’ (HBsAg negative, anti-HBs negative, and anti-HBc positive) may appear, and there may be several explanations for this (window period, remote past infection with anti-HBs decline, false positives, etc.).

HBeAg and anti-HBe: viral activity and contagiousness

Both help to assess the activity of the virus:

• HBeAg positive: usually associated with high viral replication and increased contagiousness.
  
• Anti-HBe positive: in many cases, this indicates a phase of lower viral replication and lower contagiousness, although there are variants of the virus that can have a high viral load even with negative HBeAg.
  

Key components of hepatitis C serology

In the section on hepatitis B and C serology corresponding to hepatitis C, the report is usually shorter but equally important.

Anti-HCV: the first gateway to diagnosis

Detects antibodies against the hepatitis C virus:

• Negative anti-HCV: suggests that there is no evidence of HCV infection or that the infection is very recent and antibodies have not yet developed.
  
• Anti-HCV positive: indicates that there has been contact with the virus at some point. This result alone does not distinguish between past resolved infection and active infection.
  

HCV RNA (viral load): is there active infection?

Detecting HCV RNA in the blood allows us to know whether the virus is still present and replicating:

• Detectable HCV RNA: indicates active infection (acute or chronic), requiring specific assessment by a gastroenterologist, hepatologist or infectious disease specialist.
  
• Undetectable HCV RNA in a person who is HCV antibody positive: usually indicates that the infection resolved spontaneously or following antiviral treatment.

Genotype and other tests

In some reports, you will see the HCV genotype (1, 2, 3, etc.). This classification describes variants of the virus that behave differently when exposed to certain drugs.

Today, the advent of broad-spectrum direct-acting antivirals has simplified the approach, but this information remains useful in many clinical protocols.

Main methods of hepatitis B and C serology

Hepatitis B and C serology relies on different laboratory methodologies that have improved in sensitivity and specificity over the years.

Screening techniques: automated immunoassays

Automated immunoassays on laboratory platforms are commonly used for initial screening for hepatitis B and C:

• ELISA-type tests or chemiluminescence techniques to detect HBsAg, anti-HBs, anti-HBc, anti-HCV and other antibodies.

Confirmatory and quantitative tests

When a screening serology test suggests hepatitis B or C infection, the next step is usually:

• Confirmatory antibody tests:
  
  • In hepatitis C, additional techniques have historically been used to confirm the presence of specific antibodies against different antigens of the virus.
    
• Detection of viral genetic material (HCV RNA, HBV DNA):
  
  • En hepatitis C, la detección y cuantificación del ARN-VHC confirma si hay infección activa y permite conocer la carga viral.
    
  • In hepatitis B, HBV DNA testing complements serology to assess virus replication and guide treatment decisions.

Other findings that may appear in your report

In some cases, your report may include:

• Genotype C virus: useful for guiding the choice and duration of certain treatments, although current direct-acting antivirals have simplified part of this decision.
  
• Additional markers of hepatitis B: more specific tests that help assess the risk of reactivation in people who are going to receive certain immunosuppressive treatments.

If you see abbreviations on your results sheet that you do not recognise, it is important to check them with your doctor or specialist.

What to do after learning the results

Hepatitis B and C serology is a very powerful tool, but interpretation must always be done on an individual basis.

Although this guide helps you better understand concepts such as HBsAg, anti-HBs, anti-HBc, anti-HCV, and HCV RNA, your doctor is the one who should integrate:

• Your laboratory results.
  
• Your medical history.
  
• Possible risk factors (previous transfusions, injection drug use, unprotected sexual intercourse, invasive procedures, etc.).
  

Preventative measures to protect yourself and others

Depending on the interpretation of your hepatitis B and C serology, your healthcare team may recommend:

• Hepatitis B vaccination if you are susceptible (no detectable HBsAg and no detectable anti-HBs).
  
• Protective measures to prevent infection: use condoms, do not share sharp objects or syringes, manage wounds and contact with blood correctly.
  
• Control of alcohol consumption and other factors that damage the liver, which is particularly important in people with chronic HBV or HCV infection.
  
• Inform those close to you when advised by the specialist, so that they can also be tested or vaccinated if necessary.
  

Next steps

Understanding hepatitis B and C serology markers helps you gain a clearer picture of your status with regard to hepatitis viruses. However, remember that the final interpretation should always be made by your healthcare professional.

If you need to perform hepatitis B and C serology testing or would like to expand the study with other specialised tests, Ambar Lab is a leading laboratory offering a wide range of more than 3,000 different tests, as well as ongoing technical support.

Whether you are a patient or work in healthcare, we encourage you to contact our team. We are ready to answer your questions and assist you.