Barbara Bewley
POCT Manager
Addenbrookes Hospital
Cambridge, UK
Meter manufacturers are responding to increasing demand for more sophisticated, reliable point-of-care (PoC) glucose testing devices. What is wanted is faster and easier testing, smaller sample volumes, fewer interferences and less data management. Future developments will use innovative technology and IT solutions, but in some healthcare sectors there may be a move away from conventional monitoring towards IT systems.
Introduction
Diabetes mellitus, a condition characterised by hyperglycaemia (raised blood glucose level) has many potential complications, both acute and chronic. In 2006, the World Health Organization (WHO) estimated that there were 180 million diabetic patients worldwide and, given the current rapid rate of increase, predicted that this figure will have doubled by the year 2030.
Blood glucose measuring devices were the first PoC testing instruments and still dominate the PoC market, representing a multibillion-dollar business. The main objective of PoC testing is to obtain a result more rapidly than the central laboratory. Treatment decisions can then be made that will produce an improved health outcome for the patient. Clinical and operational considerations together with technological advances have been, and still are, driving forces in the expansion of PoC testing in both the primary and secondary healthcare sectors. Home testing by people with diabetes also makes a significant contribution to the PoC testing market.
Improved glycaemic control has been shown to be beneficial to the patient – and to the healthcare economy – by reducing the frequency and severity of associated complications. Tight glycaemic control in acutely ill hospitalised patients significantly improves both mortality and morbidity but requires frequent – often hourly – glucose testing. In order to meet demands for increased PoC testing in all sectors of the market, manufacturers have produced increasingly sophisticated and technically reliable instrumentation in addition to IT solutions capable of handling effectively increased volumes of patient data.
Market changes
Changes in device technology have been driven by a general market need for smaller sample volumes, shorter test times, greater ease of use, greater strip stability and less interference. Smaller sample volumes, typically less than 2 µl, and shorter test times are advantageous for all healthcare sectors, but particularly in intensive care areas practising tight glycaemic control with frequent – hourly or sometimes half-hourly – testing. Increasingly, manufacturers are moving to a strip system with no requirement for batch coding. Underfill detection, improved shelf-life and a wider operational temperature range reduce some of the common user errors in both the professional healthcare and home use sectors.
Interference from commonly occurring substances such as uric acid, ascorbic acid, paracetamol and oxygen has been a long-term concern with many PoC testing devices. A more serious cause for concern is the interference from haematocrit, maltose and galactose. Many manufacturers have addressed these issues by changing the measuring system to reduce sensitivity to the interfering
substances, or by measuring them and applying a correction.
IT platforms have been demonstrated to improve operator and patient identification, compliance with quality control, maintenance of staff training and the ability to capture financial reimbursement data. Most manufacturers recognise that the healthcare sectors need to be able to incorporate data generated at PoC into the electronic patient record. These are the primary functions of the current
generation of connectivity solutions.
The College of American Pathologists (CAP) produced an instrument survey in April 2007 detailing features of available glucose devices and comments from manufacturers. The makers of the bedside glucose testing systems featured in CAP’s survey have responded to the current demands with new instruments and features, from multiple measuring wells to wireless capabilities.
Roche Diagnostics’ cobas© IT 1000 solution allows for management of system configurations, test and material management, operator and PoC instrument management as well as quality control and extensive reporting functions. This data management IT solution is an open system that connects PoC devices from Roche as well as those from other suppliers in a single hospital or a hospital network. Roche’s Rals TGCM informatics software, available in the US, responds to customer focus on the importance of real-time information in improving patient care. Roche offers a glycaemic adviser programme for hospitals that are just beginning to implement tight glycaemic protocols. This connects healthcare professionals with their counterparts from hospitals already successfully using tight glycaemic control. The company also plans to customise and improve access to its computerised learning tools.
Nova Biomedical has introduced the StatStrip© system to address the need for improved test accuracy and freedom from interferences: a requirement highlighted by the increased use of tight glycaemic control protocols. Trials have demonstrated that the StatStrip glucose monitoring system avoids erroneous results due to haematocrit or oxygen abnormalities, dosing and coding errors, and interferences from substances such as maltose, galactose, acetaminophen, ascorbic acid and uric acid. The StatStrip system uses a strip technology with four measuring wells rather than one. It features a six-second measuring time, 1.2-µl sample volume, highlights abnormal and critical results, and requires no calibration coding. In addition, StatStrip’s sampling system eliminates errors due to overdosing or undersampling.
This year, according to the CAP survey, Abbott plans to increase the availability of several recent enhancements to its PrecisionWeb© PoC data management system. The enhancements include reports to support tight glycaemic control protocols, online entry of manual test results and a remote monitoring system to reduce IT burdens.
Bayer Healthcare has introduced the Contour Pro©, a wireless, PDA-based connectivity solution for professional glucose monitoring. It allows management of other bedside testing such as blood pressure and temperature using secure Bluetooth connections. The Contour© meter corrects for haematocrit in the range 0–70%, uses a technology with no maltose or galactose interference and has a correction electrode in the strip to improve stability with common reducing substances. It features a five-second measuring time, 0.6 µl sample volume and requires no coding.
The future
In hospital PoC testing in particular, the need for electronic support for inventory, quality control and user management is clear, as is the need for easy access to audit data for regulatory compliance and electronic support for user training. A wider application of future wireless technology could connect diabetics with their care team in situations where mobility, transport or geography is a barrier to clinic or surgery attendance.
Innovation does not always make an immediate impact on the healthcare market. Handheld meters, invasive lancing devices and use of blood as a measurement matrix may not represent the long-term future for all sectors of the healthcare market, however. As long ago as 1988, a laser lancing device that claimed to reduce pain and discomfort was approved for use. And a study of a new handheld device that is inserted in the ear to measure blood glucose levels without painful finger sticks was published in the December 2002 issue of the American Diabetes Association journal Diabetes Care. The device isolates and measures blood glucose levels from the eardrum using the body’s natural heat emission, or thermal radiation.
Continuous monitoring of glucose systems using transcutaneous and subcutaneous interstitial fluid measurements have been available for several years but do not eliminate the requirement for some conventional finger-prick testing. In April 2006, the US Food and Drug Administration approved the MiniMed Paradigm, a real-time insulin pump and continuous glucose monitoring system. This is an open-loop system in which dosing decisions are based on sensor reading confirmed by handheld meter. The next stage is surely a closed-loop glucose testing and insulin delivery system that could maintain a normal glucose in a diabetic patient similar to the way the pancreas performs in nondiabetics.
Conclusion
There is no doubt that in the short term more sophisticated handheld devices with better performance criteria and innovative IT solutions will continue to improve patient care across the healthcare market. There may be a continuing move to integrate not just multiple PoC devices but other technologies such as blood pressure monitors and thermometers into a single wireless platform in secondary care. Home testing for some, particularly juvenile type 1 diabetics, is undoubtedly moving towards a holistic solution in the evolution of a closed-loop, intelligent glucose monitor and insulin pump. This would be a true artificial pancreas.
