COVID-19: NEGATIVE TEST RESULTS

From the outset of both PCR and Lateral Flow Tests (LFTs), the difficulty in swabbing well means:

• Positive tests should be treated as positive
• Negative tests should be treated with doubt

With a good swab sample, both types of tests are pretty reliable.  High 'sensitivity' means 'false positives' are very low:

• PCR tests
• LFT antigen tests
  

But today's news about PCR processing problems at a laboratory confirms that 'false negatives' are a major problom with testing.  So results of both types of tests should continue to be regarded as above:

• Positive tests should be treated as positive
• Negative tests should be treated with doubt