Hull York Medical School University of Hull University of York University of Liverpool Hull University Teaching Hospital NHS Trust King's College Hospital NHS Foundation Trust

BioDrive Antifungal Stewardship:

The Turnaround Time Problem

The problem

Approximately 80% of NHS microbiology laboratories send samples to other regional or national mycology laboratories for galactomannan and beta-d-glucan testing. If one or more processes are not done in a timely manner, this can potentially cause considerable delays for the patient’s clinical team to receive the result.

Turnaround time (TAT)

A common perception is that most of the delay is due to the regional or national laboratory. However, a recent letter from the UK National Mycology Reference Laboratory in England, available here, states that this is not the case. Despite the huge increase in requests for galactomannan and beta-d-glucan testing, mean TAT has decreased and is currently <24 hours for both tests.

The TAT calculation (right), as reported by referring laboratories, includes both sample and result transit times and associated delays, and the reference laboratory TAT.

What are the consequences of a delayed test?

These tests are only likely to be impactful if done within a certain timeframe. Evidence, available here, suggests that both biomarkers come up positive at least 4 days prior to symptom development.

 

1. Test is negative but delayed: it may lead to unnecessary further tests and a delay in stopping unnecessary empiric antifungal therapy.

2. Test is positive but delayed: it may delay important additional investigations or potentially life-saving antifungal therapy.

3. Results do not impact clinical care: important NHS funds are wasted. For reference, the existing NHS tariff for each of the biomarkers used in the BioDriveAFS trial is approximately £60 per test.

A haematologist's perspective

In the following video, Dr Dave Allsup, Senior Lecturer in Haematology with an Honorary NHS appointment with Hull University Teaching Hospitals NHS Trust, talks about the BioDriveAFS trial and the importance of TATs for a practicing clinician.

References

  1. Borman, A.M., et al. (2021). Fungal biomarker testing turn-around-times at the UK National Mycology Reference Laboratory: Setting the record straight. Journal of Infection, 83(6), pp.e1-e3. Here: https://doi.org/10.1016/j.jinf.2021.10.010 
  2. Pazos, C., et al. (2005). Contribution of (1→ 3)-β-D-glucan chromogenic assay to diagnosis and therapeutic monitoring of invasive aspergillosis in neutropenic adult patients: a comparison with serial screening for circulating galactomannan. Journal of Clinical Microbiology, 43(1), pp.299-305. Here: https://doi.org/10.1128%2FJCM.43.1.299-305.2005
  3. Morrissey, C.O., et al. (2013). Galactomannan and PCR versus culture and histology for directing use of antifungal treatment for invasive aspergillosis in high-risk haematology patients: a randomised controlled trial. The Lancet Infectious Diseases, 13(6), pp.519-528. Here: https://doi.org/10.1016/S1473-3099(13)70076-8