What does C and T mean on a COVID test?

By now, most people in the UK have had to make themselves familiar with a COVID test, and with over 500 million tests taken in this country alone to date, the chances are that you will have taken a Coronavirus test, if not several. It is important when reading to bear in mind that not every test will be exactly the same, however, they all work in the same way so will have most of their features in common with other tests.

Whether or not you have had to take a test, if you have at least seen information about COVID tests you will have noticed that most of the lateral flow tests have different letters and markings, most notably the large C and T letters which indicate the outcome of the test.

So what does C and T mean on a COVID test, why were these letters chosen, and what does it mean if your test has a line next to these letters?

What does C and T mean on a COVID test?

What does the letter C mean on a COVID test?

The C on a COVID test stands for Control.

When taking a lateral flow test, you should always see a line next to the letter C on the testing strip. This is the case whether you have COVID or not, and is not an indication that you have contracted the virus.

The C indicates that the test should be working properly and the strip is being properly saturated with the liquid from the dropper tube. If a C does not show up, then the results of the test are unlikely to be reliable, as the test is not working correctly.

A positive COVID-19 test will show a line next to BOTH the letter C and the letter T on the testing strip. For more information about how to use a lateral flow test properly at home, read the NHS step-by-step guide on how to properly use a home test.

The test works by having the end of the strip where you normally drip your test sample from the extraction tubes already coated in a substance, usually including an antibody. When a liquid is poured onto the sample end, it saturates the test strip (this is the ‘flow’ in ‘lateral flow’), and the ‘C’ line checks for that antibody. This proves that the test is working and that the substances are properly flowing over the test strip.

The fact that this happens via capillary action on a flat strip is the ‘lateral’ part of lateral flow.

What does the letter T mean on a COVID test?

The letter T on a COVID test simply stands for Test.

This is the part of the test that you will be looking for to indicate whether you have tested positive for COVID-19 or not. A test with two lines, one next to the letter C and one next to the letter T indicates a positive COVID result.

If you have the symptoms of Coronavirus or if you have recently tested positive, then it is important to follow medical advice on what to do. For information on what to do if you suspect or know that you have COVID-19, read the NHS guide here.

What do the other markings on a COVID test mean?

Most COVID tests, at least in the UK, will have more markings on them than just the letters C and T.

You may have noticed the letter S is also on there, indicating where on the test you are instructed to drop the liquid from the extraction tube. The letter S in this case stands for ‘Specimen’ or ‘Specimen Well’ and is used as a marker to show you where to put your sample.

Another common feature that you may see on a COVID test is a square QR code. A QR code works the same way as a barcode on an item in the supermarket but is usually designed for use with a smartphone. In this particular instance, the QR codes are used with the NHS app in order to log test results, especially during the large scale test-and-trace rollout during the height of the pandemic.

Similarly, the long number at the top of many tests acts as a serial number to help with identification. Sometimes, there is a line or a space to write an ID number for further identification and record-keeping. Nowadays, these are less likely to be used, but during the height of the Coronavirus pandemic these were more important.

Get COVID tests at your local pharmacy

Hopefully, now we have answered the question of ‘what does C and T mean on a COVID test?’. Now that the government has ended universal free testing, you are likely to have to pay for your test, unless you meet the requirements for free tests. As stated on the NHS website, the only people still eligible to receive free COVID tests in the UK are:

• People with health conditions which means they are eligible for COVID-19 treatments

• People who require testing before entering hospital for surgery or other procedure

• People who work within the NHS or in adult social care

• In some circumstances, people who have recently been asked by a GP or healthcare professional to get tested

For everybody who does not fall into one of these criteria, testing is no longer available for free. By choosing to get your COVID test at a local pharmacy, you can be assured of quick results without having to travel for them. For information on why you should get your COVID tests at your local pharmacy, read our full guide here..

If you are in the Camberley, Frimley, Farnborough and surrounding areas and require a COVID-19 test, VSM Pharmacy stock Rapid Antigen Tests as well as Fit-to-Fly PCR Tests.

For any other services, including online prescriptions, or if you are just after some friendly, professional advice, contact us today using the form on our website, or by calling 01276 21002