Kurin Lock for blood culture collection

The evidence suggests that Kurin Lock reduces blood culture contamination rates

4.1 All 12 studies showed a reduced blood culture contamination rate after introducing Kurin Lock. Most of the studies were based in the US but there were 3 quality improvement studies based in NHS emergency departments. Most of the studies were in adults but there was 1 study in children. Although the evidence base was limited, the committee considered it plausible that Kurin Lock would lead to the positive outcomes associated with reduced blood culture contamination.

More evidence is needed to understand the resource impact of false-positive blood culture results

4.2 There is a lack of direct evidence of the downstream resource impact of using Kurin Lock. By reducing the blood culture contamination rate, the number of false positives should also be reduced. This is expected to have an impact on a patient's length of stay and antibiotic use. The clinical experts advised that there is uncertainty in the length of stay for people who have a blood culture taken and that many factors influence this. The length of stay data used in the economic model was from Skoglund 2019, based in the US. The key parameters were that a person with a true negative blood culture result would have a hospital stay of 5 days, and a person with a false-positive result would have a hospital stay of 7 days. One clinical expert stated that a mean difference of 2 days hospital stay is not plausible in clinical practice. The expert explained that other test results and clinical information are routinely used to help decide if a blood culture result is contaminated. So, in their opinion only a small proportion of people with a false-positive blood culture result would have additional treatment and a longer hospital stay. The committee agreed with the EAG's view that the Alahmadi (2010) study, which estimated longer hospital stays associated with false positives compared with Skoglund 2019, was not generalisable to the NHS because of the high proportion of people in intensive care. The committee agreed that the 2‑day difference from Skoglund (2019) may not represent NHS clinical practice, and that further evidence of the resource impact in the NHS should be generated.

4.3 Further evidence is also needed on the impact of false positives on antibiotic treatment. The clinical experts advised that most people with suspected sepsis would start antibiotic treatment before the results of the blood culture test were available. The committee considered that using Kurin Lock is not likely to have a significant impact on antibiotic stewardship. The committee noted that data on staff adherence is also important to determine if this reduces over time or in busy periods, and the impact on blood culture contamination rates.

There would be no change in practice when using Kurin Lock compared with standard blood culture collection

4.4 According to the clinical experts, Kurin Lock is easy to use and needs minimal training. The clinical experts agreed that Kurin Lock was appropriate for use in the secondary care blood culture sampling pathway, to reduce blood culture contamination rates. It could replace standard blood culture collection in most cases apart from when people have central lines. They advised that Kurin Lock may reduce pressure in the emergency department and improve outcomes for patients by reducing the number of contaminated blood culture samples.

The cost of Kurin Lock is high compared with standard blood culture collection

4.5 The high cost of Kurin Lock compared with standard blood culture collection is a barrier to using it in the NHS, unless there is better evidence showing its impact on resources. One clinical expert commented that his hospital considered the Kurin Lock cost too high and it has explored using an alternative approach to reduce contamination rates. The committee understood that the cost saving from the economic modelling relied on the high device cost being offset by a reduction in resource use, including hospital length of stay, associated with fewer false-positive results. Further evidence generation is needed to show that these cost savings will be realised in NHS clinical practice.

Kurin Lock is most likely to be cost saving in settings with a high baseline contamination rate

4.6 The committee and clinical experts agreed that there are usually higher blood culture contamination rates in the emergency department than other hospital wards, and noted that the economic modelling used an emergency department setting. In published literature, contamination rates of up to 9% were reported in NHS emergency departments. But clinical experts stated that it could be significantly higher. One clinical expert stated that they had reduced contamination rates through staff training, ensuring samples are not taken from peripheral cannulas and introducing an additional blood bottle, which is used to isolate the first few millilitres from the blood culture sample. They advised that this approach reduced blood culture contamination rates, but the change in practice needs to be regularly reinforced and may be time-consuming. Another expert had trialled this approach before using Kurin Lock and felt that Kurin Lock is easier to adopt, and from their experience works just as well with cannulas as venepuncture.

The EAG's updated model is more plausible than the company's base case and most appropriate for decision making

4.7 The company's base-case model used an emergency department setting. It used a daily ward stay cost taken from patient-level data from 1 NHS trust, which was described as a non-elective short stay cost. This was applied as a daily cost for the duration of the patient stay. The EAG did not have access to this cost data and considered the daily costs very high compared with other economic models for guidance development. The EAG used a non-elective short stay cost as the first day of stay cost, and then calculated excess stay costs for additional days using costs from NHS Cost Collection data. The committee agreed with the changes the EAG made to the company's base-case model. It considered that the lower daily hospital stay cost used by the EAG was appropriate. Accurate information on the costing of the hospital stay and the length of stay would help reduce uncertainty in the economic modelling.

The length of stay difference and the cost associated with this affects the cost saving potential of Kurin Lock

4.8 If the difference in length of stay for people with true negative blood culture results and false-positive blood culture results is overestimated, then the cost saving is reduced. This could lead to Kurin Lock being cost incurring rather than cost saving. The EAG confirmed that there is no length of stay difference data directly related to Kurin Lock that can be used instead of the Skoglund (2019) values to reduce the uncertainty of the model results. Because the main driver is the length of stay difference, the committee was cautious in its interpretation of the base-case results.

Kurin Lock is cost saving in the EAG's base case, but the sensitivity analysis indicates uncertainty

4.9 There is uncertainty about the cost effectiveness of introducing Kurin Lock, because the sensitivity analysis showed that it can be cost saving or cost incurring. Probabilistic sensitivity analysis of the EAG model reported a 62% probability that Kurin Lock would be cost saving compared with standard blood culture collection. The committee considered that the lack of evidence on the resource impact from using Kurin Lock is a significant limitation of the economic model. Further evidence generation including information on the length of hospital stay from NHS hospitals using Kurin Lock could be used to revise the economic model.

Evidence generation should provide data to reduce uncertainty in the economic modelling

4.10 The key uncertainties about using Kurin Lock in the NHS are related to its cost effectiveness. Sensitivity analysis showed that Kurin Lock can be cost saving or cost incurring depending on the parameters used, particularly around the length and cost of hospital stay. The clinical experts advised that length of stay and treatment after a blood culture test is complex and depends on many factors. The committee concluded that evidence generation alongside using Kurin Lock in the NHS would provide an opportunity to collect resource impact data that could inform economic modelling in a future review of the guidance. NICE will review the guidance once new evidence is available.