Patients who meet the following criteria, regardless of epidemiological links, should be swabbed:

  • requiring admission to hospital, and
  • have either clinical or radiological evidence of pneumonia, or
  • acute respiratory distress syndrome, or
  • influenza like illness


Interpretation of negative COVID-19 result
Performance of PHE – Cambridge COVID-19 assay based on ≥ 8 genomes copies/reaction: Sensitivity: 100%; Specificity: 99.4%; PPV: 94%; NPV: 100% and Efficiency: 99.5%.

A test may have a very high analytic but low clinical performance if the sample is collected from an inappropriate anatomical site or at an unsuitable time concerning the disease. Please consider a negative PCR result in the context of clinical features. If required, repeat the test by appropriate sampling: nose and throat swabs are suitable for patients with the features of URTI while sputum or bronchoalveolar lavage is needed from patients with the characteristics of LRTI.

Help to locate hidden swabs
Please can all wards, pods etc check to see if any swabs are being stored in the back of cupboards.

We still have swabs in stock in the hospital and at Public Health England (PHE) Cambridge, however, there is a national shortage, so we may need to consolidate supplies.

Anyone who has an additional stock of swabs should contact Martin Strickland and David Pearce at PHE.