Everything you need to know about herpes testing in Australia
What this page covers. Herpes testing in Australia is more nuanced than most other STI tests. The right test depends on whether you have symptoms now, when you were last exposed, and what question you actually want answered. This page explains the different tests, what they do, what they do not do, and how to make sense of a result.
What herpes is. Herpes is a common viral skin infection caused by herpes simplex virus (HSV). There are two types. HSV-1 is the cold-sore type carried by around two-thirds of Australian adults. HSV-2 is the type more often found on the genitals and is carried by around one in seven adults. Both types can affect either area. The virus enters through tiny cracks in the skin during close contact. It then stays in nerve cells for life. Most people who have it have no symptoms or only very mild ones.
Two main test types: swab and blood test. The two tests answer different questions. A swab is taken from a blister, ulcer or itchy spot. It tests for the live virus on the skin and can identify HSV-1 or HSV-2. A blood test (called an HSV IgG test) looks for antibodies the immune system makes weeks after infection. The swab tells you what is happening on your skin right now. The blood test tells you whether you have ever been infected.
If you have symptoms — get a swab. The swab is the test commonly recommended for anyone with a possible outbreak. The technique is simple. The collector unroofs the blister, swabs the base, and sends the sample to a pathology lab for polymerase chain reaction (PCR) testing — a sensitive lab method that detects the virus’s genetic material. It is very sensitive when a lesion is fresh and can identify the HSV type in one test. Test as early in the outbreak as possible. Once a sore has scabbed over, the result becomes less reliable. See herpes testing in Melbourne for local access. Pathology samples can also be collected at any of the pathology collection centres in Australia.
If you have no symptoms — understand the blood test limits. HSV IgG testing is the only option without skin signs. Current Australian guidelines do not recommend routine herpes blood testing for people without symptoms. The result is often hard to interpret and can cause distress without changing management. The test is more useful in specific situations: a partner has been diagnosed; you are pregnant or planning pregnancy; you have unexplained recurrent symptoms; or you want to know your status before a new relationship. Talk to a GP first about whether the result is likely to change anything you would do.
What the HSV IgG index value means. Australian labs report HSV IgG as an index value. Less than 1.1 is negative. Greater than 3.5 is very likely positive. Between 1.1 and 3.5 is a low-positive grey zone where false positives are common. The biggest cause of a false low-positive is cross-reactivity with HSV-1. If you have ever had a cold sore, you carry HSV-1 antibodies. These can sometimes produce a low-positive HSV-2 reading that is not real. A low-positive result with no symptoms should not be treated as a confirmed diagnosis. Confirmation involves either a Western blot test or a PCR swab during any future symptoms.
IgG vs IgM. IgG and IgM are both antibodies but they behave differently. IgG appears slowly over 2 to 12 weeks after infection and stays for life. IgM appears earlier but is unreliable in adults. Many people with old infections still test IgM positive. Many people with new infections test IgM negative. International guidance now advises against IgM testing in adults outside specific newborn or research situations. Stick with IgG.
Time before a test is reliable. The waiting time between possible infection and a reliable test result depends on which test you are taking. For a swab during a symptomatic outbreak, the test is reliable as soon as a lesion appears. For an HSV IgG blood test, antibodies usually become detectable by 6 to 8 weeks. Some people take up to 12 weeks. Testing earlier than 6 weeks risks a false negative. If a first blood test is negative but you suspect a recent exposure, repeat at 12 weeks. See when to test after exposure for waiting times on other STIs.
Should your partner be tested? Routine partner testing for herpes is not as straightforward as for chlamydia or gonorrhoea. Many people with HSV have no symptoms. They may already carry it without knowing. A partner blood test can be useful in specific situations. For instance, when one of you is pregnant or planning pregnancy. Or when there is a clear question about whether to use daily treatment to reduce passing it on. A GP discussion is often more useful than a blanket test recommendation.
What happens if a swab is positive. A positive swab confirms genital herpes and identifies the type. The next step is a follow-up consult to talk through treatment options. If this is a first outbreak, the GP will discuss whether episodic or daily treatment would suit you. They will also talk about transmission reduction and what to expect with future outbreaks. Future outbreaks are usually milder and shorter than the first one. See herpes treatment for what treatment looks like in practice. A new diagnosis is also a reasonable trigger for a broader STI screen. The most common companion infections to check for are chlamydia and gonorrhoea.
What happens if a blood test is positive but you have no symptoms. This is the harder result to make sense of. A high-positive IgG (index above 3.5) in someone without symptoms most likely means you carry HSV but have never had a noticeable outbreak. Many people in this situation never develop symptoms. The result does not mean you need treatment. It does mean some practical conversations. With current partners about lower-risk practices. And with future obstetric care if pregnancy is on the cards. A GP review of the actual numbers and your individual situation is more useful than reacting to the result alone.
What happens if a result is negative. A negative swab during a current outbreak almost certainly rules out herpes. The swab can occasionally miss the virus if the lesion is old or partially healed. A negative blood test is more nuanced. It can mean you do not have HSV. It can also mean you were infected too recently for antibodies to show up. The 6-to-12-week window applies. If symptoms develop later, retest with a swab from the new lesion rather than another blood test.
Anonymity and confidentiality. All STI testing in Australia is confidential. Test referrals go to your phone or email. Results return to the ordering clinician. Nothing is sent to your regular GP, your workplace, or anyone else without your consent. Herpes is not a notifiable infection in Australia. There is no public health register and no contact tracing requirement. A diagnosis stays between you and the doctor.
Want to discuss your specific situation? A Specialist GP phone consult can talk through which test you need, what your result means, and the next step. See the hero section above for booking details. For Melbourne residents, see herpes testing in Melbourne for local access. For step-by-step guidance on testing windows across all STIs, see when to test after exposure.
Frequently asked questions
Not sure what you have? Compare symptoms side by side in our STI Comparison Guide — plain English, no jargon.
Not sure when to test? See our When to Get an STI Test guide — how long after exposure to test, testing frequency, and what to do after exposure.
At least 6 weeks. Antibodies usually become detectable in the blood between 6 and 12 weeks after infection. Some people take a few weeks longer. Testing earlier than 6 weeks risks a false negative. If a first test is negative and you suspect a recent exposure, repeat at 12 weeks. For symptoms now, a swab from a lesion does not need a waiting period — it is reliable as soon as a sore appears.
An index of 1.8 falls in the low-positive grey zone (1.1 to 3.5). Results in this range have a relatively high rate of false positives. The most common cause is cross-reactivity with HSV-1 antibodies from past cold-sore exposure. A low-positive HSV-2 result in someone with no symptoms should not be treated as a confirmed diagnosis. Confirmatory testing options include a Western blot test (sent interstate) or a PCR swab if symptoms develop later. A GP review of the actual value and your history is worthwhile before drawing conclusions.
Because the test result often does not change anything practical. HSV is very common (around two-thirds of Australians carry HSV-1, around one in seven carry HSV-2). Many positive results in symptom-free people are either false positives in the low-positive range, or detections of infection that was never going to cause symptoms. Routine testing can cause significant distress for a result that does not lead to treatment or change behaviour in a useful way. Targeted testing — for a specific clinical reason — is more helpful than blanket screening.
No, not in adults. IgM is an antibody that appears early in infection, but for HSV it is unreliable in adults for diagnostic purposes. People with old, long-standing infections often still test IgM positive (because the virus reactivates). People with new infections sometimes test IgM negative. Many international labs have stopped offering IgM testing for HSV altogether. Australian guidance recommends IgG only for adult diagnosis.
It depends on what you want the result to tell you. If you have symptoms or have ever had unexplained genital irritation, yes — a swab during any future episode is the most useful test. If you have no symptoms but want to know whether you carry HSV, an IgG blood test is an option, but be ready for a possibly-ambiguous low-positive result. Many couples find that a discussion with a GP about how to reduce passing it on is more useful than a blanket test recommendation. Routine partner testing for HSV is not a clear-cut yes the way it is for chlamydia or gonorrhoea.
Yes, occasionally. A PCR swab is very sensitive when a lesion is fresh and unroofed. The yield drops as the lesion ages. Once a sore has scabbed over, the swab is much less reliable. False negatives also happen when sampling technique is poor (not unroofing the blister), or when the lesion is healing. If you have classic recurrent symptoms but a swab comes back negative, that does not necessarily rule out herpes — another swab on a fresh lesion is often more reliable than going to a blood test.
Talk to your obstetric team before deciding. Pregnancy changes the risk calculation. First-time HSV infection in the last three months of pregnancy carries the highest risk of passing it to the baby during birth. A baseline blood test now can help establish whether you already carry the virus (in which case a new infection is unlikely). The decision is rarely just about the test itself — it is about what your team would do with each possible result, including whether to consider antiviral cover or change birth planning.
Standard pathology testing has a Medicare item number, which appears on your Medicare claim history. If you use Medicare or private insurance to pay for the test, the line item shows up on those records. For a fully private payment with no rebate, nothing flows to Medicare or insurance. Herpes is not a notifiable infection in Australia, so there is no public health register and no contact tracing process. Discuss your specific situation with the GP if record visibility matters for you.
Only if circumstances have changed. A new partner is the most common trigger. A specific concern about a partner’s diagnosis is another. New unexplained genital symptoms are a third. Routine annual retesting in the absence of these triggers is not recommended — it tends to generate false-positive worry without changing what anyone would do. If you do retest, a swab during any symptomatic episode is more useful than a repeat blood test.
A Western blot is a more specific antibody test for HSV that can resolve some of the false-positive results seen with the standard IgG test. It is the reference standard in research settings. In Australian routine practice it is not the first-line test, because it is more complex, takes longer, and is not commonly offered by Australian labs — samples often need to be sent interstate or overseas. Some specialists arrange it specifically for low-positive IgG results when confirmation matters. For most people, a PCR swab during any future symptoms is a more practical confirmation route.
