Benefits of point-of-care testing
Over recent years, point-of-care testing has been embraced by healthcare professionals in community and acute care settings.
Point-of-care systems that use a finger prick blood sample as opposed to a more invasive and laborious venous sample offer significant advantages in terms of time, cost, and patient comfort.
The role of NT-proBNP monitoring in heart failure
One condition where point-of-care monitoring is now being increasingly used is heart failure (HF). Despite severe cardiac dysfunction, many patients treated for HF and discharged from hospital do not report symptoms . It has been reported that, in contrast to symptoms, B-type-natriuretic peptide (BNP) is an objective prognostic marker better predicting survival than traditional prognostic indicators in HF. Patients with high risk for early rehospitalisation and death can be effectively identified by assessing levels of natriuretic peptides at discharge.In addition, natriuretic peptides may be useful objective indicators of short-term improvement or deterioration.
The measurement of the amino-terminal fragment of BNP, NT-proBNP, offers two diagnostic opportunities in managing patients with HF. First, global risk assessment, allowing intensive management by specialists to focus on those patients with the greatest risk of decompensation. Second, it facilitates assessment of short-term changes in wall stress, allowing anticipation of decompensation and medication adjustments in advance.
Berger et al found that compared with routine multidisciplinary care of HF patients, multidisciplinary plus NT-proBNP-guided care improved outcomes for patients post discharge. Compared with routine care, NT-proBNP guided-care significantly reduced days of HF hospitalisation (P<0.0001) and the combined endpoint of death or HF hospitalisation (P<0.05).
NT-proBNP point-of-care testing devices are now available and are becoming more and more sophisticated, with some devices measuring a range of parameters including not only NT-proBNP, but also troponin T, D-dimer, myoglobin, and CK-MB. These devices are appropriate for use in both acute and outpatient settings, facilitating diagnosis in a timely fashion.
The importance of getting INR monitoring right
The use of warfarin is increasing at a rate of 10% per year, so it’s worth re-emphasising the importance of monitoring the international normalised ratio (INR), the gold standard indicator of effectiveness and risk of bleeding during warfarin therapy. The target range is 2.0-3.0 for most indications, with the ideal measurement being around 2.5, although higher levels may be desirable for certain patients. While the lower limit demarcates the threshold for clinical effectiveness, the upper limit is set to minimise bleeding. Getting the INR right is important because around 11% of adverse drug events in Australia are coagulation related, at an estimated annual cost of $100 million for hospital management alone.
It has been shown that better INR control occurs with more, rather than less frequent testing. Standard laboratory INR monitoring contributes significantly to the cost of anticoagulation, is invasive and can interrupt patients’ lives and thus may be a barrier to proper warfarin use. Thus, point-of-care monitoring is an attractive option. Point-of-care devices are widely accepted by patients and are reported to reduce pain and improve quality of life compared with venous blood testing, while accuracy is comparable with venous blood INR measurement.