Evaluation of Hematocrit Interference With MyStar Extra and Seven Competitive Devices

Abstract

Prevalence of abnormal hematocrit values (HCT) in diabetic is a phenomenon that is underestimated by physicians and diabetes nurse educators. HCT is generally considered to be quite stable in the range of 40-45% and blood glucose meters for patient self-testing are usually set to function properly with HCT concentration in this "normal range." However, a thorough investigation of the hematocrit distribution in an urban community has demonstrated a HCT-range of 30-50% in a healthy reference population. In community patients, the observed HCT ranged between 20% and 60%, and in hospital patients it was 10% to 70%. Patients in the intensive care units showed levels between 15% and 40%.1 In older patients also suffering from various diseases, these variations can even be more pronounced and may have an impact on the patient's prognosis, for example, in patients with kidney disease.2 In daily routine, changes in the hematocrit levels can be the result of lifestyle interventions (eg, smoking, prolonged exercise), can come with demographic conditions (eg, age), and can be induced by disease-and drug-related conditions (eg, hematological disorders, hypermenorrhea, pregnancy, or renal disease) and by environmental conditions (eg, stay in high mountains, seasonal variation). [3][4][5] Hematocrit interference has previously been identified as a source for inaccuracies of blood glucose meter readings in daily routine. 6,7 In meters employing static electrochemistry, Method: Venous heparinized blood was freshly drawn, immediately aliquoted, and manipulated to contain 3 different blood glucose concentrations (50-80 mg/dL, 150-180 mg/dL, and 350-400 mg/dL) and 5 different HCT levels (20-25%, 30-35%, 40-45%, 50-55%, and 60-65%). After careful oxygenation to normal blood oxygen pressure, each of the 15 different samples was measured 8 times with 2 devices and 2 strip lots of each meter (32 measurements/meter/sample). YSI Stat 2300 served as laboratory reference method. Next to determination of the mean absolute relative deviation (MARD), stability to HCT influence was assumed, when less than 10% difference occurred between the highest and lowest mean glucose deviations in relation to HCT over all tested glucose ranges (HIF: hematocrit interference factor).

Diabetes, trekking and high altitude: recognizing and preparing for the risks

“…However, they should do so with the knowledge that meter accuracy may be compromised and testing conditions may be difficult (cold, dark, windy, dusty, snowy, rainy, etc.). Alterations in haematocrit levels with altitude may also reduce meter accuracy, but about half of new meters tested have been shown to reliably correct for the potential influence of haematocrit level on the meter result [30]. Without adjustment for temperature and humidity, elevated blood glucose concentrations have been reported to be underestimated by~1-2% for every 300 m of ascent gained [29].…”

“…Without adjustment for temperature and humidity, elevated blood glucose concentrations have been reported to be underestimated by~1-2% for every 300 m of ascent gained [29]. Alterations in haematocrit levels with altitude may also reduce meter accuracy, but about half of new meters tested have been shown to reliably correct for the potential influence of haematocrit level on the meter result [30]. Although, in theory, oxygen saturation could impact meter accuracy in those using glucose oxidase (GOX) enzymes, it does not appear to impact meter accuracy in those using the glucose dehydrogenase (GDH) reaction pathway, at least to altitudes of~3000 m [31].…”

Advances in Patient Self-Monitoring of Blood Glucose

“…6,7 We saw a major further accuracy improvement with the introduction of the Contour XT (4.8% in patients 8,9 ) and finally our first study with Contour Next, the same device and strip platform tested by Bendini et al, 1,2 resulted in an MARD 1.3% with samples processed in our laboratory. 10 One reason, why the accuracy of the Contour Next platform in comparison to other devices has finally reached such a high level, may be seen in the elimination of hematocrit interference by means of a mathematical correction algorithm. The efficacy of employing algorithms similar to dynamic electrochemistry to correct for hematocrit interference is dependent on the determination of specific equation factors derived from laboratory experiments.…”

“…10 Other technology advances bringing the meters and strips to such high accuracy standards included, but were not limited to change of strip and electrode design, change of electrode materials, change in the strip chemistry, and improvement of the mathematical algorithms and in the device software.…”

Histogram analysis for smartphone-based rapid hematocrit determination

“…The interference of a blood hematocrit is usually considered as a potentially important issue by many health-care professionals [1,2]. The normal hematocrit-level is considered as rather constant, and it is in the range of 40% to 54% for adult males and 37% to 47% for adult women [3][4][5].…”