SELFCheck Lyme Disease Test

What is the SELFCheck Lyme Disease Test?

The SELFCHECK Lyme Disease Test checks for immunoglobulin M (IgM), one of the first types of antibodies your immune system produces in response to Borrelia bacteria (1,2).

The test uses a lateral flow device, similar to a rapid COVID-19 test, to show whether these antibodies are in your blood. Unlike a laboratory blood test, it doesn't measure antibody levels or check for other antibody types, such as IgG, which usually develop later.

You’ll get your results at home in 10 minutes, without needing to send a sample to a laboratory (1). The manufacturer recommends testing two to six weeks after a suspected tick bite, as antibodies can take time to become detectable (1,2).

• Tests for anti-Borrelia IgM: Antibodies your body produces after a bite by an infected tick

• At-home testing: Uses a small finger-prick blood sample

• Quick results: Read your result at home after 10 minutes

• Simple result format: Coloured lines indicate whether antibodies have been detected

• Single-use kit: One test per pack, with no laboratory return required

This is a screening test and cannot diagnose Lyme disease. Positive results suggest a possible infection that needs assessment by your GP. Negative results cannot rule out infection. If you have symptoms, seek medical advice rather than relying on a home test.

What is Lyme disease and how do you get it?

Lyme disease is a bacterial infection spread to humans through bites from infected ticks (3). Ticks are tiny spider-like creatures found in UK woodlands, parks and gardens. Not all ticks carry Borrelia bacteria, so a tick bite doesn't necessarily mean you'll develop Lyme disease (3).

If an infected tick has bitten you, one of the most recognisable signs is an expanding circular or oval rash around the bite, called erythema migrans. It often looks like a bullseye, but not always. It usually appears within one to four weeks of getting bitten, but can appear up to 3 months later (3).

If you develop the erythema migrans rash, speak to your GP rather than taking a home test. The rash is such a strong sign of Lyme disease that NICE recommends diagnosing and treating it without waiting for blood test results (4).

Not everyone develops a rash, and some people don't even notice being bitten. The SELFCHECK Lyme Disease Test can check whether your body has produced antibodies against Borrelia bacteria, although testing without symptoms isn't routinely recommended (4).

Left untreated, Lyme disease can sometimes cause serious complications affecting the joints, heart or nervous system (3,4).

When should you take a Lyme disease test?

The Lyme Disease Test is to be used two to six weeks after a suspected tick bite (1,2).

Testing too early can give you a false-negative result, even if you've been infected. This is because the test looks for IgM antibodies, rather than the Borrelia bacteria themselves. Your body can take two to four weeks to produce enough antibodies for the test to pick up.

The antibodies generally become easier to detect as the infection progresses. In the first two to four weeks, antibodies are detectable in around 40% to 60% of people with Lyme disease, but detection rates increase to around 70% to 90% in the following four to six weeks (2).

IgM levels can drop later on, so waiting longer than six weeks won't necessarily give you a more reliable result.

If you have symptoms of Lyme disease, don't wait to take the test. Speak to your GP urgently.

How accurate is the SELFCheck Lyme Disease Test?

In manufacturer testing, the SELFCHECK Lyme Disease Test produced the same result as laboratory antibody tests in around 89% of cases (2).

But the test can miss infections even when used within the recommended two-to-six-week window. During this period, the manufacturer reports a sensitivity of 53.8%, meaning the test may miss nearly half of positive cases and give a false-negative result (2). This is more likely the earlier you test.

False-positive results are also possible, where the test detects antibodies even though you don't have Lyme disease. This can happen when antibodies produced in response to other infections or autoimmune conditions react with the test (1,2).

For these reasons, a positive result needs medical assessment, while a negative result cannot completely rule out Lyme disease.

What are the limitations of the SELFCheck Lyme Disease Test?

The SELFCHECK Lyme Disease Test can accurately check for an early antibody response to Borrelia bacteria, but it does have limitations (1,2):

• It doesn't check for all Lyme disease antibodies. Your body produces different antibodies at different stages of the infection. This test only looks for IgM, whereas laboratory tests can check for both IgM and IgG, which the body makes later.

• It can miss an infection. If you test too early, your body may not have produced enough IgM antibodies to detect. IgM levels can also fall later in infection, meaning a negative result doesn't always rule out Lyme disease.

• A positive test doesn't always mean Lyme disease. Antibodies produced in response to other infections, such as glandular fever and syphilis, or autoimmune conditions can sometimes react with the test and give a positive result.

• It can't tell you if you currently have Lyme disease. Even if the test detects anti-Borrelia IgM antibodies, the test can't tell you when you were infected, whether the infection is still active, or whether you have fought it off.

When should you speak to a doctor?

Ask for an urgent GP appointment if you develop symptoms of Lyme disease, whether your home test is positive or negative. Symptoms to look out for include (3,4):

• A circular or oval rash that gradually spreads

• Fever, chills or flu-like symptoms

• Persistent headaches or unusual tiredness

• Muscle or joint pain

If your home test is positive but you feel well, contact your GP to discuss the result and whether further testing is needed.

Some complications of Lyme disease need more urgent attention. Seek urgent medical help if you develop facial weakness, a severe headache with a stiff neck, or a racing or irregular heartbeat. Call 999 if you have life-threatening symptoms.