Ensuring effective point-of-care testing

Point-of-care testing has been a feature of the healthcare landscape for many years, with a variety of tests – such as blood gas analysis and glucose measurements – now routinely performed at the bedside in all acute care areas. As best practice criteria and diagnostic testing technology advance, there is the potential for more assays to be performed at the point of care. Most recently, perhaps the biggest sea change has been in ITU where, following the pan-European Surviving Sepsis Campaign1 to reduce the high mortality rates for severe sepsis, many departments have added serum lactate to their POC blood gas analyser test profiles. Serum lactate is a critical biomarker for severe sepsis, and getting a result in literally a minute – rather than waiting for a laboratory result which, even when labelled urgent, is reliant on sample transport and takes significantly longer – is a huge advantage. Similarly, albeit in an outpatient setting, testing for D-dimer at the point of patient care is proving invaluable as a screen to help rule out the presence of venous thromboembolism (VTE) in atrisk patients. An excellent example of this can be seen in patients attending DVT clinics, where they would initially be scored for risk and those at high risk historically would then be prescribed anticoagulant therapy and referred for an urgent ultrasound scan. D-dimer, measured at the clinic with a 20-minute turnaround of results, now gives clinicians a quick and reliable way to rule out VTE, saving considerable time and money in inappropriate medication and unnecessary scans. These savings are also being realised in A&E departments, with cardiac patients, in particular, reaping the benefit. Depending on each individual hospital’s criteria, patients presenting with low risk chest pain usually have to wait for 12 hours after the onset of pain for a timespecific blood test that rules out a cardiac event. Despite the majority of these cases being negative, this delay has significant cost implications, often requiring an unnecessary admission for the patient. Being able to rule out a cardiac event in just a few hours by screening at the point of patient care for a panel of three separate cardiac markers – troponin I, CKMB and myoglobin – reduces the strain on resources, and offers reassurance to patients by ruling out a cardiac condition far earlier.

 Developing POC platforms

The development of robust and reliable POC platforms requires more than simply the technology to miniaturise the assay itself. To be successful, POC instruments must be safe and easy to use for nonlaboratory staff, with secure access control, calibration and audit trail functions to ensure accurate and reliable results – as well as compliance with local and national guidelines – while standing up to the rigours of a busy hospital environment.