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Antimicrobial Resistance

Sepsis or not? Molecular Gram, direct from blood in under four hours


Dr Helen V Benett

Market Development Manager, Momentum Bioscience LTD.

Introducing a new class of product where all organisms in a whole blood sample can be put into a test, without which an early  Gram result would not be possible.

A crucial, unmet need for sepsis diagnostics is the rapid determination if a bloodstream infection (BSI) is present or not and identifying the causative organisms and their antibiotic sensitivity pattern. 

The Gram stain result is of great value in clinical treatment of sepsis, despite the limited amount of information it provides, because it is the first lab test result provided to the clinician.

Saving time saves lives

Faster results for septic patients have been reliably shown to reduce morbidity and mortality. Generally speaking, the sicker the patient, the greater the value of earlier targeting of antimicrobial therapy. A study by Kumar et al. in patients with septic shock showed a 7.6% increase in mortality for each hour of delay in appropriate antimicrobial treatment1.

Is it sepsis or not?

Our newly automated ETGA test is being piloted in studies at two different US sites, with a further site planned in the UK. With reportable results within one day, this is a vast improvement on the current standard of up to five days.

It is envisaged that this rule-out test, with its high negative predictive value of 99.5%, will have significant impact on reducing the use of unnecessary antibiotics. It will also have further benefits, such as helping to determine a patient’s suitability for discharge.

Results in less than four hours

In a recent project co-funded by the UK’s innovation agency, Innovate UK, we have shown feasibility of our new direct from blood test that will uniquely identify the presence or absence of a bacterial or fungal BSI, followed by the categorisation of the causative organisms as Gram positive, Gram negative or yeast, all in less than four hours.

Our rapid molecular Gram categorisation could enable earlier change of therapy; a switch from IV to oral, de-escalation or a switch to antifungals. It could also enable faster focus of antibiotics in unknown BSI cases. This new test may also help guide decisions to run more complex, expensive tests for identification and antimicrobial susceptibility. All of which helps towards improved patient management and overall cost savings to the hospital.

None of the currently available rapid BSI diagnostics achieve this combination of determining presence or absence followed by Gram categorisation. 

1 Crit Care Med 2006, 34 (6) 1589-96

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