Reasons for 'invalid' self test results

Reasons for 'invalid' self test results

Wednesday 24th June 2020

Invalid test results are extremely rare and almost always due to the instructions not being followed as written. The photo here shows a test cassette where not enough blood has been added and an invalid result.

It is a legal requirement in the UK and EU that all self test kits undergo user trials with lay persons as part of the independent scientific and clinical checks to show that most people find the instructions easy to follow and can interpret the results correctly. Only if the results of these trials are positive is a self test kit allowed to be sold to the general public (IVD Directive 98/79EC).

All batches of SELFCheck self test kits are manufactured and assembled in ISO13485 certified laboratories where quality control testing is performed on each batch that is made to show that the tests perform as intended.

Nevertheless, occasionally, for one reason or another, a test user might get an 'invalid' result where neither the control line or test line appear. Due to the way these tests are manufactured, it is unlikely that this is due to a malfunction of the device, instead an invalid result is usually due to;

1) the diluent drops were added by mistake to the results window instead of the sample well
2) too much or too little blood being applied to the sample well (as in photo) or;
3) not enough drops of buffer diluent being added.

This is why it is so important to read the instructions carefully before you start your test or touch the components.

If you are unlucky enough to get an invalid result, don't worry, just contact us and we will do what we can to help.