Those differences are not trivia. The route of spread tells you who is likely to come into contact with each virus, the usual course tells you whether a single infection is behind someone or needs long term follow up, and the choice of test decides whether an infection is found at all.
Hepatitis means inflammation of the liver, and the letters A through E label five viruses that damage the same organ while being otherwise unrelated to each other 1. They belong to separate virus families, carry different genetic material, and travel by different routes. They were grouped alphabetically because they were discovered one after another as causes of the same clinical picture, not because they are relatives.
The five differ in almost every way that matters practically. Hepatitis A and hepatitis E are picked up by swallowing the virus. Hepatitis B, C and D move through blood and body fluids. Hepatitis B carries DNA, the others carry RNA. Hepatitis D is the odd one out, an incomplete virus that cannot build its own outer coat and has to borrow one from hepatitis B 1.
What they share is the result. All five can inflame liver cells, push liver enzymes up, and produce the same set of symptoms, which is exactly why the letters cannot be told apart at the bedside 8. A clinician looking at a yellow tinge in the eyes and a raised liver enzyme panel knows the liver is irritated, not which virus, or indeed whether a virus is involved at all. Alcohol, excess liver fat, autoimmune liver disease, inherited conditions and some medicines can all inflame the liver as well. That is why the word hepatitis is a description, not a diagnosis, and why a specific blood test is the only way to name the cause.
Two of the five spread by the faecal to oral route and three spread through blood and body fluids, and that single split explains most of the differences between them 2.
| Virus | Main route of spread | Other recognised routes | Usual course | Can it persist? | Vaccine available |
|---|---|---|---|---|---|
| Hepatitis A | Faecal to oral, contaminated food and water | Close household contact, sexual contact | Acute, usually resolves | No | Yes |
| Hepatitis B | Blood and body fluids | Sexual contact, shared injecting equipment, unsterile medical or tattooing equipment | Acute, may persist | Yes | Yes |
| Hepatitis C | Blood to blood | Shared injecting equipment, unsterile procedures, transfusion before donor screening | Often silent, frequently persists | Yes | No |
| Hepatitis D | Blood and body fluids, only in people who also carry hepatitis B | The same routes as hepatitis B | Co-infection or later superinfection | Yes | No separate vaccine, hepatitis B vaccination prevents it |
| Hepatitis E | Faecal to oral, often through contaminated water | Undercooked meat from infected animals in some settings | Acute, usually resolves | Rarely, mainly in people with weakened immunity | Not widely available |
The faecal to oral viruses follow sanitation. Where water treatment and food handling are reliable, hepatitis A and hepatitis E outbreaks are uncommon and tend to be traced to a single contaminated source or to travel. The blood borne viruses follow exposure to another person's blood, which includes shared needles, reused or inadequately sterilised equipment in medical, dental, tattooing and piercing settings, and transfusion in places or eras without donor screening 2.
Hepatitis B is the most transmissible of the blood borne three. It is present in semen and vaginal fluid as well as blood, so sexual transmission and household contact matter. Hepatitis C transmits far less efficiently by sexual contact and is overwhelmingly a blood to blood infection.
Hepatitis A and hepatitis E are acute infections that the immune system almost always clears, while hepatitis B, C and D can become long term 1. This is the single most useful dividing line on the whole page, because it decides whether an infection is an episode or a condition that needs monitoring for decades.
After hepatitis A, the immune system produces antibodies that persist for life, and reinfection does not occur. Hepatitis E behaves similarly in people with normal immunity, although the virus can persist in people whose immune system is suppressed 1.
Hepatitis B is different, and age at infection is the main factor. Research suggests that most adults who are infected clear the virus, while infection acquired in infancy or early childhood is far more likely to become long term 4. Hepatitis C frequently persists after the acute phase, and because the acute phase is usually silent, many people only learn of it years later through a blood test 3.
This matters because persistence is where the long term liver risk sits. Chronic infection with hepatitis B or hepatitis C is associated with progressive scarring of the liver and with liver cancer, and these two viruses account for the bulk of the global burden of liver disease caused by hepatitis 7. Hepatitis D, when it is present alongside hepatitis B, is associated with a more rapid course than hepatitis B alone 6. None of that is a forecast for an individual. It is the reason chronic infection is followed over time rather than filed away.
All five viruses produce much the same symptoms when they produce any at all, which is why symptoms cannot identify the letter 8. The familiar picture includes fatigue that is out of proportion to activity, loss of appetite, nausea, aching muscles, a low grade fever, discomfort under the right ribs, dark urine, pale stools, and yellowing of the whites of the eyes and the skin.
The more important point is how often there are no symptoms. Acute hepatitis C is commonly silent, and chronic hepatitis B and chronic hepatitis C can run for years without a single noticeable sign while liver changes accumulate quietly 3.
Timing differs between the viruses. Hepatitis A and hepatitis E tend to declare themselves within weeks of exposure with a fairly abrupt illness. Hepatitis B has a longer incubation and can arrive more gradually. Hepatitis C often never announces itself.
The practical conclusion is uncomfortable but useful. Feeling fine is not proof of an uninfected liver, and feeling unwell does not identify which virus is responsible. Symptoms decide whether someone seeks care; blood tests decide what is found.
Hepatitis D is an incomplete virus. It carries its own genetic material but cannot produce its own outer envelope, so it wraps itself in the surface antigen made by hepatitis B and can only replicate in someone who already carries that antigen 1. No hepatitis B, no hepatitis D.
This happens in two patterns. In co-infection, both viruses arrive at the same time, and the illness is usually acute. In superinfection, the delta virus arrives later in someone who already carries long term hepatitis B, and this pattern is associated with a more aggressive course 6.
There are two practical consequences. First, hepatitis D testing is only meaningful in people whose hepatitis B surface antigen is positive, which is why it is almost never a standalone request. Second, vaccination against hepatitis B may help prevent hepatitis D as well, because the delta virus has no way to establish itself without the B surface antigen 6. Whether vaccination is appropriate for a given person is a decision for a licensed provider.
Hepatitis D is also the easiest of the five to miss, simply because it is not included in standard panels unless someone thinks to ask for it in a person already known to carry hepatitis B.
Both are swallowed rather than injected, but hepatitis E is more often waterborne and, in some settings, comes from animals, while hepatitis A spreads mainly from person to person and through contaminated food 1.
Large hepatitis E outbreaks follow contaminated drinking water, particularly where sanitation has broken down. Elsewhere, sporadic cases are linked to undercooked meat from infected animals, which makes hepatitis E unusual among the five in having an animal reservoir 2. Hepatitis A, by contrast, is a human virus that moves through households, childcare settings, food handling and close contact.
A second difference is persistence. Hepatitis A does not become chronic. Hepatitis E generally does not either, but it can persist in people whose immune system is suppressed, and in that situation it is looked for specifically rather than assumed to have cleared 1.
A third difference is prevention. A vaccine against hepatitis A is widely used, while a hepatitis E vaccine is not available in most places, so prevention for hepatitis E rests on safe water, careful food preparation and thorough cooking of meat 2.
ALT is an enzyme concentrated inside liver cells, so a raised level shows that liver cells are leaking their contents, not which virus is responsible. Typical lab reference ranges run roughly 7 to 56 U/L for men and 7 to 33 U/L for women. FitScript's optimal range is 10 to 25 U/L for men and 8 to 19 U/L for women. Optimal ranges are FitScript's optimization targets, not diagnostic cut offs, and reference ranges vary by lab, age and sex. ALT can also sit inside the standard range during long standing infection, so a normal number does not rule a virus out. The ALT guide covers how the marker is measured, what moves it and how to read a result in detail.
Each virus has its own antibody or antigen test, and a confirmatory test that detects the virus itself, so naming the cause means asking for the right test rather than a general liver panel 5.
| Virus | Usual first line blood test | What a reactive result points to | Common next step |
|---|---|---|---|
| Hepatitis A | IgM antibody to hepatitis A | Recent or current infection | IgG or total antibody indicates past infection or vaccination |
| Hepatitis B | Surface antigen, plus core antibody and surface antibody | Current infection, past exposure, or vaccine response, depending on the pattern | Hepatitis B DNA to measure virus in the blood |
| Hepatitis C | Hepatitis C antibody | Exposure at some point, past or present | Hepatitis C RNA to confirm current infection |
| Hepatitis D | Hepatitis D antibody, requested when the hepatitis B surface antigen is positive | Exposure to the delta virus | Hepatitis D RNA |
| Hepatitis E | Hepatitis E IgM and IgG antibodies | Recent or past infection | Hepatitis E RNA in blood or stool |
Two layers are doing different jobs here. Antibody tests record that the immune system has met the virus, which may have been last month or thirty years ago. Nucleic acid tests look for the virus itself and answer the question that actually matters, which is whether an infection is present now 5.
Hepatitis B is the only one of the five routinely read as a pattern rather than a single number. Surface antigen indicates the virus is present. Core antibody indicates past or present exposure. Surface antibody on its own, without core antibody, usually reflects vaccination. Reading those three together is what separates an active infection from an old resolved one from an immune response to a vaccine, and that interpretation belongs with a clinician.
For hepatitis C specifically, the two step sequence of antibody first and RNA second is the standard approach, and the hepatitis c test guide walks through what each step shows and how the results fit together.
Because antibodies outlive the infection that produced them. A reactive hepatitis C antibody test tells you the immune system encountered the virus, and it stays reactive whether the virus cleared on its own, was dealt with years ago, or is still present, which is why a nucleic acid test is needed to settle the question 5.
The same logic applies across the group. Total antibody to hepatitis A is usually a record of immunity, from past infection or vaccination, rather than a sign of anything active, while the IgM form points to something recent. Hepatitis E IgG can persist long after a mild illness that was never recognised at the time.
This is where the observation, meaning, next step sequence is worth applying deliberately. The observation is the test result and nothing more. The possible meanings are several, and they include recovery and vaccination, not only active infection. The next step is a confirmatory test chosen by a clinician, not a conclusion drawn from the first result.
It also explains why people are sometimes told they tested positive and then told, after a second test, that there is no virus in their blood. Nothing went wrong. The first test answered a question about the past and the second answered a question about the present.
There is a window after exposure when a person is infected but the test can still come back negative, and its length depends on the virus and on which test is used.
Antibodies take time to appear, because the immune system has to recognise the virus and mount a response first. Tests that look for the virus directly, by detecting its genetic material, turn positive earlier than antibody tests in acute infection 5. Incubation periods also differ between the viruses, with hepatitis B generally taking longer from exposure to illness than hepatitis A 1.
The practical meaning is simple. A test taken very soon after a known exposure can be falsely reassuring, and the timing of repeat testing is a clinical decision that depends on the virus involved, the type of exposure and the test available. Someone with a specific recent exposure is better served by asking a clinician when to test and when to retest than by reading a single early negative result as a final answer.
For long standing, unknown exposures, timing is not an issue at all. Someone wondering about an event years ago will have had ample time to develop antibodies, and a standard antibody test is a reasonable starting point.
Liver enzymes alone describe irritation, so they are usually read next to markers of bile flow, liver function and blood counts. A fuller picture usually includes AST, alkaline phosphatase, GGT, bilirubin, albumin, a full blood count including platelets, and a clotting measure such as prothrombin time.
AST sits in liver cells but also in muscle and red blood cells, so the relationship between AST and ALT gives a hint about where the signal is coming from. Alkaline phosphatase and GGT rise more when bile flow is obstructed or irritated than when liver cells themselves are inflamed. Bilirubin is the pigment behind jaundice and dark urine, and it rises when the liver cannot process or excrete it normally.
Albumin and clotting markers are different in kind. They reflect what the liver is still manufacturing, so they speak to function rather than injury. A low platelet count can accompany advanced scarring, which is why a routine blood count is informative beside a liver panel.
This is the context in which broad testing earns its place. FitScript's membership includes 150+ biomarkers tested per year, with results interpreted by Atlas, FitScript's AI health advisor, so a single out of range enzyme is read next to the rest of the panel rather than on its own. No panel of general markers can name a virus, though. That still requires the specific tests above.
Plenty, which is why a raised enzyme is a prompt to investigate rather than a verdict. Alcohol intake, excess fat stored in the liver, autoimmune liver conditions, inherited conditions affecting iron or copper handling, and thyroid and muscle disorders can all push liver markers up. Some medicines and supplements can raise liver enzymes too; ask your prescriber about anything you are taking before changing anything.
Everyday factors matter more than people expect. Hard or unaccustomed resistance training can raise ALT and AST for days afterwards, because damaged muscle releases these enzymes as well. A heavy drinking weekend, a recent viral illness unrelated to the hepatitis group, or rapid weight change can all shift the numbers. A single mildly raised result taken the morning after a long gym session is a weak signal.
The constructive response is to repeat the test under calmer conditions, with several days of no unusual exercise and no alcohol, and to look at the pattern across several markers rather than one. A result that stays outside the standard range on repeat testing is worth discussing with a clinician, who decides what else to check and in what order.
What is never appropriate is deciding that a raised enzyme must be a virus, or that it cannot be one. Both conclusions skip the only step that answers the question, which is a virus specific test.
Exposure follows the route of spread, so the risk profile is different for the food and water viruses than for the blood borne ones 2. For hepatitis A and hepatitis E, the relevant history is travel to or residence in areas with limited sanitation, drinking water of uncertain quality, undercooked meat in some settings, and close contact with someone already infected.
For hepatitis B, C and D, the relevant history includes any sharing of injecting equipment, medical, dental, tattooing or piercing procedures with equipment of uncertain sterility, transfusion before donor screening was routine, needlestick injuries at work, household or sexual contact with someone carrying hepatitis B, and birth to a parent carrying the virus 2.
Because chronic infections are frequently silent, testing is often worthwhile in the absence of symptoms. A large share of people carrying hepatitis B or hepatitis C worldwide have never been diagnosed, and improving detection is central to control efforts 7.
In plain terms, anyone with a plausible past exposure, a persistently raised liver enzyme with no obvious explanation, or a family history of hepatitis B has a reasonable question to put to a clinician. Who should be tested, and for which viruses, is a clinical judgement rather than a self assessment.
A first positive result is the start of a sequence, not the end of one. The usual next step is confirmation, because an antibody test and a test for the virus itself answer different questions, and the second is needed before anything is concluded 5.
If a current infection is confirmed, the picture is usually filled in with repeat liver enzymes, markers of liver function, an assessment of how much scarring is present, and in chronic hepatitis B an assessment of how actively the virus is replicating. Household and sexual contacts may be offered testing and, where appropriate, vaccination, and a licensed provider decides who that applies to.
Management differs sharply between the letters. Acute hepatitis A and hepatitis E are generally monitored while the body clears the infection. Treatment decisions belong to a licensed provider who has reviewed the full picture.
The other half of the sequence is practical. Ongoing monitoring of liver markers, honest reporting of alcohol intake, and telling every prescriber about the diagnosis so that anything processed by the liver is considered carefully, all sit inside the follow up plan a clinician sets.
Any unexplained liver enzyme result outside the standard range deserves a conversation, and some situations deserve one promptly. Yellowing of the eyes or skin, urine that is persistently dark, unusually pale stools, severe pain under the right ribs, persistent vomiting, or new confusion or drowsiness are all reasons to contact a clinician promptly rather than waiting for a routine appointment.
A known exposure is another. Someone who has had a needlestick injury, shared injecting equipment, or close contact with a person known to carry hepatitis B should raise it with a clinician quickly, because the timing of testing and of any preventive step is time sensitive and only a licensed provider can judge it.
Less urgent but equally real is the quiet case. Mildly raised enzymes that keep returning, long standing fatigue without explanation, or a past exposure that has never been tested for are all reasonable reasons to ask whether virus specific testing makes sense. A suboptimal result is information, not a verdict, and the next move is a question for a clinician rather than a conclusion to reach alone.
This article is educational and is not medical advice. Discuss your results and any treatment with a clinician or licensed provider who can see your full history.
Hepatitis B, C and D can persist beyond the initial infection, while A almost never does and E usually does not except in people with a weakened immune system. Persistence is the reason B and C are followed over years with repeat blood tests. Whether an infection has become long term is confirmed by testing for the virus itself, not by symptoms.
No. Each virus has its own antibody or antigen test, and a general liver panel such as ALT and AST only shows that the liver is irritated. A clinician usually decides which of the five to test for based on exposure history, symptoms and liver results.
Not on its own. The antibody test shows the immune system met the virus at some point, which may have been years ago and may have resolved. A follow up test that looks for the virus genetic material in the blood is what confirms whether an infection is current, and a clinician orders and interprets it.
Yes. ALT and AST can sit inside the standard reference range during long standing infection, so a normal liver panel does not rule out hepatitis B or C. If there is a plausible exposure, virus specific testing is the only way to answer the question.
Both are swallowed rather than injected, most often through contaminated water or food. Hepatitis E is also found in some animals in certain settings, so undercooked meat is a recognised source. Safe water, careful food handling and thorough cooking reduce the chance of exposure.
The delta virus cannot build its own outer coat and borrows one from hepatitis B, so it can only establish an infection in someone who already carries the hepatitis B surface antigen. That is why a hepatitis D antibody test is requested after a positive hepatitis B surface antigen and almost never on its own.
Vaccines exist for hepatitis A and hepatitis B, and hepatitis B vaccination also prevents hepatitis D because that virus depends on B. There is no vaccine for hepatitis C, and a hepatitis E vaccine is not widely available. Whether vaccination is appropriate for a particular person is decided by a licensed provider.
It can be, because chronic hepatitis B and C often cause no symptoms for years while changes build in the liver quietly. A past exposure, an unexplained raised liver enzyme or a family history of hepatitis B are all reasonable reasons to ask about testing. A clinician decides which tests make sense and when.