Background United Kingdom Standards for Microbiology Investigations limits the pre-analytical delay of blood cultures to a maximum of four-hours between collection and incubation. Compliance with this delay standard is a measure of the ability of a microbiology service to support the management of sepsis which is a life-threatening complication of infection. A positive blood culture confirms the infection and an early result is critical to the effective management of the condition. Delayed results lead to the prolongation of empiric broad spectrum antimicrobial therapy which is considered a causal factor in the emergence of antimicrobial resistance. This retrospective observational study documents compliance with the standard by microbiology services in England in 2022/23. The impact of laboratory centralisation on the ability of microbiology services to comply with this standard is examined.

Methods Freedom of Information requests were submitted to 116 National Health Service Trusts/administrative units in England requesting retrospective audit data showing compliance with the recommended pre-analytical delay standard. Data relating to service configuration and cost were also requested.

Results Responses were received from 89 Trusts (76.7%) managing 146 hospitals. Overall, the rate of compliance was low, with only four hospitals (2.7%) showing full compliance and 31.5% showing >80% compliance.

Conclusions Poor rates of compliance with the PAD standard are a concern as prompt attention to blood cultures improves patient outcomes from sepsis and supports antimicrobial stewardship. Laboratory centralisation has resulted in withdrawal of staff and facilities from some hospitals with insufficient investment in others, leading to a demonstrable inability of many hospitals to comply with this standard. Compliance will require investment in microbiology services. The financial implications of the improvements proposed should be evaluated in the context of overall health care and community benefits.

The authors have declared no competing interest.

The author(s) received no specific funding for this work.

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