All of us have seen someone prick their finger to determine their blood glucose levels through a portable glucometer while we may not understand, the small instrument is of great importance for people battling Diabetes Mellitus. It helps them monitor their glycemic index from wherever they are, rather than driving to a medical setting. The use of a glucometer is known as POC glucose testing.
What is POC glucose testing, you may ask?
It is a part of a broader term, known as point-of-care (POC) testing and is our topic of interest for this article. Here, you will understand POC testing, how it reinformed the healthcare industry, and how it helps in diabetes management
What is Point of care (POC) testing?
Point of care testing, or POC testing, is a diagnostic test conducted outside the vicinity of a laboratory. Instead, the test is carried out near the patient’s care and provides immediate results.
There are various interchangeable terms for point-of-care testing. For instance, it is also known as bedside, near-patient, and mobile testing. Each of these terms represents a tool adequate for rapid testing that healthcare providers perform impromptu for instant results.
Point-of-care testing requires a handheld electronic device or a molecular collection tool. The most common examples include blood glucose monitoring, thermometers, and home pregnancy tests.
Anyone from a healthcare professional to the patient can carry out POC testing. It all depends on where the test is required. For instance, at a medical facility, a pharmacist, radiologist, or RN can employ point-of-care testing. Similarly, at the site of an accident, the first responder may be responsible for conducting the test. Moreover, at home, the patient or their kin can take the test for immediate tests. Hence, by employing the test anytime and anywhere, POC testing is a means for remote patient monitoring.
Point-of-Care Testing and Value-added Healthcare: The Link:
Point-of-care testing has been a ground-breaking discovery in the healthcare sector. According to TechTarget, it has contributed to easy diagnosis, efficient monitoring, timely diagnosis, and prevention of chronic diseases.
It empowered both the spectrums of the healthcare industry, the physician, and the patient. POC testing helped patients take charge of their health and make conscious decisions. On the other hand, it facilitated the physicians to determine fluctuations in various physiological processes in real-time and take prompt actions.
It aids and abets in diagnosing and managing chronic conditions and acute infections. Point-of-care testing helps healthcare providers identify any condition within a single encounter. The strategy, therefore, has improved access to care, counseling, and patient outcomes. Therefore, many community pharmacies are readily accommodating POC testing on their premises to amplify their patient care services.
Moreover, a study in the journal of Medicine states that POC testing has improved patient satisfaction by reducing the need for blood samples. By doing so, the test has also helped physicians who struggled with a high patient influx rate.
Point-of-Care Testing for Diabetes Management:
Point-of-care testing has helped the healthcare industry significantly by simplifying the management of diabetes mellitus. So much so, today is one of the most widely-employed tools for determining blood glucose levels. It facilitates hyperglycemic patients to keep an eye on their blood sugar levels whenever and wherever they are. As a result, they can prevent complications that may arise due to staggering glucose levels.
However, its greatest importance lies in managing hospitalized patients. POC blood glucose test is widely employed by patients for its accurate quantitative result, compact size, cost-efficacy, and easy-to-use mechanism.
In units such as intensive care or critical care, healthcare providers need to vigilantly check the patient’s blood sugar levels. Since any fluctuation can aggravate the existing critical condition, POC testing helps determine glycemic levels in real time. The instant results help caregivers to derive prompt remedial strategies.
Furthermore, in hospitalized patients, continuous blood glucose level monitoring is essential to determine the type and quantity of medications and food.
The Limitations of POC Glucose Testing:
Even though Point-of-care glucose testing has reformed hospital-based glycemic management programs, it still poses certain limitations. Various research has shown POC glucose meters to deliver inaccurate results, putting the patient’s life at risk. One of the reasons why POC glucose testing isn’t deemed appropriate for hospitalized patients is the interference of the body’s physiological process with the device’s reading. Certain substances and conditions commonly persist in critically-ill patients. These include oxidizing/reducing substances and conditions like anemia or hyperoxemia (high pO2 levels). In the presence of such interfering substances, the glucometer delivers false results and compromises the patient’s health.
Let’s find out how different substances and condition causes POCT glucose meters to depict false results:
Ascorbic acid and acetaminophen:
Ascorbic acid is one such interfering substance, which leads to high but inaccurate blood glucose readings on some devices.
Another substance that might interfere with the measurement of the POC glucose meter is acetaminophen. Acetaminophen is a drug usually administered intravenously to manage perioperative pain. While no study has testified to its effect on the glucometer’s efficiency, some healthcare professionals are skeptical regarding its use.
Low hematocrit levels:
Furthermore, low hematocrit levels (a symptom of anemia) are also attributed to false high glucose levels when compared with the standard plasma-based method. In such cases, the caregivers modify their strategy accordingly, which increases the risk of hypoglycemia.
Amongst all factors influencing the reading of the POC glucose meter, the interaction with peritoneal dialysis is the worst. In peritoneal dialysis (PD), Icodextrin is commonly used for greater ultrafiltration (UF) volume. During the process, Icodextrin is metabolized to maltose, a type of sugar that consists of two glucose molecules and is also known as double sugar. The older version of POC glucose meters often mistake maltose for glucose and report a higher reading. Such POCT glucometers employ glucose-1-dehydrogenase (GDH) reactions, which are not specific to glucose. Hence, in the presence of any other blood sugar, such as maltose or galactose, the device overestimates the glucose levels.
A 2013 article cited the tragic case of a woman who suffered from severe hypoglycemic brain injury secondary to an insulin infusion. The patient was on peritoneal dialysis, during which her POC meter reading was 150-200mg/dL. As a treatment, the patient received 115 units of insulin in 24 hours. However, her CLD glucose values were within the range of 20-40mg/dL. The excess insulin administration caused the blood sugar levels to decrease beyond the recommended levels. To prevent such incidents, FDA has curated a list of meters that caregivers should not use for patients with PD.
Hypoglycemia and hyperlipidemia:
Hypoglycemia is a term used to describe low blood glucose levels. Hyperlipidemia, on the other hand, describes elevated concentrations of lipids in the blood. These might be very different conditions, but they do have one thing in common: their influence on POC glucose testing. Conditions like hypoglycemia, hyperlipidemia, increased bilirubin, and uric acid levels interfere with the accuracy of a POCT glucose meter.
Validation of POC Glucose Meters in Medical Settings:
To reduce the chances of errors and their possible consequences, FDA has issued guidelines for the use of POC glucose testing in hospitals. If the POC glucose meter is used according to the FDA’s approved intended instructions, it does not need formal validation. In such cases, the verification of the devices is done to verify their accuracy, precision, and analytical measurement capability. On the other hand, for ”off-label” use, the POCT glucose meter should undergo high complexity classification.
POC glucose testing has helped caregivers significantly in delivering prompt and impeccable care. Today, the healthcare industry can leverage the POCT glucose meters to a greater extent due to reduced chances of errors. Hence, by employing the device strictly for the intended use and managing its data properly, healthcare providers can use POC glucose testing to its maximum benefit.