Effect of ambient temperature on analytical performance of self-monitoring blood glucose systems.

BACKGROUND: The analytical quality of self-monitoring of blood glucose (SMBG) can be affected by environmental conditions such as temperature. The objective of this study was to determine the influence of (1) a shift in the ambient temperature immediately before measurement and (2) taking measurements in the lower and upper part of the operating temperature range. METHODS: Nine different SMBG systems on the Norwegian market were tested with heparinized venous blood (4.8 and 19.0 mmol/L). To test the shift in ambient temperature effect, the glucometer and strips were equilibrated for 1 h at 5°C or 1 h at 30°C before the meter and strips were moved to room temperature, and measurements were performed after 0, 5, 10, 15, and 30 min. To test the lower and upper temperature range, measurements were performed at 10°C and at 39°C after 1 h for temperature equilibration of the glucometer and strips. All these measurements were compared with measurements performed simultaneously on a meter and strips kept at room temperature the whole time. RESULTS: Six of nine SMBG systems overestimated and/or underestimated the results by more than 5% after moving meters and strips from 5°C or 30°C to room temperature immediately before the measurements. Two systems underestimated the results at 10°C. One system overestimated and another underestimated the results by more than 5% at 39°C. CONCLUSIONS: The effect on analytical performance was most pronounced after a rapid shift in the ambient temperature. Therefore patients need to wait at least 15 min for temperature equilibration of affected meters and strips before measuring blood glucose.

The prevalence of self-monitoring of blood glucose and costs of glucometer strips in a nationwide cohort.

OBJECTIVE: This study used nationwide data to determine the prevalence of self-monitoring of blood glucose (SMBG) among all non-institutionalized persons living in Norway and to estimate the prevalence of SMBG among diabetes patients, the frequency and cost of SMBG, and the use of different glucometers. METHODS: This retrospective, descriptive study is based on data of sales of glucometer strips to non-institutionalized persons in Norway in 2008. The data included gender, age group, month of purchase, sales place, type of strips, number of packages dispensed, and cost of strips. Additionally, statistics on sales of insulin and oral antidiabetes medications were obtained from the Norwegian Prescription Database. RESULTS: A total of 96,999 persons purchased strips, a prevalence of 2%. Approximately 70% of diabetes patients practiced SMBG. An average patient used 1.7 strips per day, and younger patients purchased more strips than older patients. Fewer than 50% of patients performed glucose measurements daily. One percent of patients used more than 10 strips daily and was accountable for 8% of total costs. Most patients used only one type of strips, but the number of strips purchased increased with the number of different strips. The average annual cost of strips was 446 euro per person. CONCLUSIONS: Two percent of all non-institutionalized inhabitants and an estimated 70% of patients using diabetes medication purchased SMBG strips. A small percentage of the patients incurred a substantial proportion of the costs. This, along with the fact that over half of the patients monitor less than once per day, calls for tighter follow-up of diabetes patients.

Implementation of a method for glucose measurements in community pharmacies.

OBJECTIVES: We aimed to implement a method for glucose measurements that could be used as a comparison method for asessing patients' self-monitoring of blood glucose. Further, we investigated whether pharmacies could achieve an analytical quality comparable to glucose measurements performed in general practice. METHODS: Sixteen Norwegian pharmacy employees were trained in glucose measurement, quality control and blood sampling. The comparison method, HemoCue Glucose 201+, was validated in four steps: (1) estimation of the variation between the HemoCue instruments to be used at the 16 pharmacies, (2) comparison between HemoCue results and a laboratory glucose method, (3) monitoring quality by internal quality controls and (4) an external quality-assessment scheme. The pharmacies' results of the external quality assessment were compared to those of 359 general practices. KEY FINDINGS: The coefficient of variation for HemoCue instruments was 6.1% at the low level and 1.7% at the normal and high levels. Bias was negligible at the normal level. The coefficients of variation for internal quality controls were 4.5, 1.5 and 1.2% for the low, normal and high levels, respectively. All pharmacies achieved good precision and acceptable or good trueness in the external quality assessment. The pharmacies exhibited significantly lower variation between sites (2.2 and 1.2%) than general practices (3.8 and 2.9%) on both external quality-assessment samples. CONCLUSIONS: Given correct training and the establishment of a system of quality assurance, pharmacies are capable of obtaining glucose measurements that can be used as comparison measurements for controlling patients' meters. The pharmacies had external quality-assessment results comparable to general practice.

Quality assessment of patients' self-monitoring of blood glucose in community pharmacies / Evaluación de la calidad de la auto-monitorización de glucosa sanguínea de pacientes en farmacia comunitaria

Objective: To evaluate diabetes patients' self-monitoring of blood glucose using a community pharmacy-based quality assurance procedure, to investigate whether the procedure improved the quality of the patient performance of self monitoring of blood glucose, and to examine the opinions of the patients taking part in the study. Methods: The results of patient blood glucose measurements were compared to the results obtained with HemoCue Glucose 201+ by pharmacy employees in 16 Norwegian community pharmacies. Patient performance was monitored using an eight item checklist. Patients whose blood glucose measurements differed from pharmacy measurements by more than 20% were instructed in the correct use of their glucometer. The patients then re-measured their blood glucose. If the results were still outside the set limits, the control procedure was repeated with a new lot of glucometer strips, and then with a new glucometer. The patients returned for a follow-up visit after three months. Results: During the first visit, 5% of the 338 patients had measurements that deviated from pharmacy blood glucose values by more than 20% and user errors were observed for 50% of the patients. At the second visit, there was no significant change in the analytical quality of patient measurements, but the percentage of patients who made user errors had decreased to 29% (p < 0.001). Eighty-five percent of the patients reported that they used their blood glucose results to adjust medication, exercise or meals. Fifty-one percent of the patients reported a greater trust in their measurements after the second visit. Eighty percent of patients wished to have their measurements assessed yearly. Of these patients, 83% preferred to have the assessment done at the community pharmacy. Conclusion: A community pharmacy-based quality assessment procedure of patients' self monitoring of blood glucose significantly reduced the number of user errors. The analytical quality of the patients´ measurements was good and did not improve further during the study. The high analytical quality might be explained by a selection bias of participating patients. Patients also reported increased confidence in their blood glucose measurements after their measurements had been assessed at the pharmacy (AU)

Objetivo: Evaluar la auto-monitorización de la glucemia de pacientes diabéticos que utilizan un procedimiento de aseguramiento de la calidad en farmacia comunitaria, investigar si el procedimiento mejoró la calidad de la ejecución de la monitorización del paciente, y examinar las opiniones de los pacientes que tomaron parte en el estudio. Métodos: Los resultados de las medidas de glucemia de los pacientes se compararon con los resultados obtenidos con un HemoCue Glucose 201+ por los empleados de la farmacia en 16 farmacias comunitarias noruegas. Se monitorizó la actuación del paciente utilizando un check-list de 8 puntos. Se educó en el uso del glucómetro a los pacientes cuyos valores de glicemia diferían en más de un 20% de los medidos en la farmacia. Después los pacientes volvieron a medir su glucemia. Si los resultados estaban aún fuera de los límites se repetía el procedimiento con un nuevo paquete de tiras de glucómetro, y después con un nuevo glucómetro. Los pacientes volvieron para una visita de seguimiento tres meses después. Resultados: Durante la primera visita, el 5% de los 338 pacientes tuvieron mediciones malas que se desviaron de las de la farmacia en valores superiores al 20% y se observaron errores en el 50% de los pacientes. En la segunda visita, no hubo cambios significativos en la calidad analítica de las medias de los pacientes, pero el porcentaje de usuarios con errores disminuyó al 29% (p<0,001). El 85% de los pacientes informó que utilizaban los resultados de su glucemia para ajustar la medicación, ejercicio o comidas. El 51% de los pacientes informó que tenían una mayor confianza en su medición después de la segunda visita. El 80% de los pacientes deseaba que se le evaluasen sus mediciones de glicemia anualmente. De estos pacientes, el 83% prefería que la evaluación se hiciese en la farmacia comunitaria. Conclusión: Un procedimiento de evaluación de la calidad de la auto-monitorización de glucemia realizado en farmacia comunitaria redujo significativamente el número de errores de los usuarios. La calidad analítica de las medidas de los pacientes fue buena y no mejoró durante el estudio. La alta calidad analítica podría explicarse por un sesgo de selección de los pacientes participantes. Los pacientes también informaron e un aumento de confianza en sus medidas de glucemia después de que sus mediciones fueses evaluadas en la farmacia (AU)

Quality assessment of patients' self-monitoring of blood glucose in community pharmacies.

OBJECTIVE: To evaluate diabetes patients' self-monitoring of blood glucose using a community pharmacy-based quality assurance procedure, to investigate whether the procedure improved the quality of the patient performance of self monitoring of blood glucose, and to examine the opinions of the patients taking part in the study. METHODS: The results of patient blood glucose measurements were compared to the results obtained with HemoCue Glucose 201(+) by pharmacy employees in 16 Norwegian community pharmacies. Patient performance was monitored using an eight item checklist. Patients whose blood glucose measurements differed from pharmacy measurements by more than 20% were instructed in the correct use of their glucometer. The patients then re-measured their blood glucose. If the results were still outside the set limits, the control procedure was repeated with a new lot of glucometer strips, and then with a new glucometer. The patients returned for a follow-up visit after three months. RESULTS: During the first visit, 5% of the 338 patients had measurements that deviated from pharmacy blood glucose values by more than 20% and user errors were observed for 50% of the patients. At the second visit, there was no significant change in the analytical quality of patient measurements, but the percentage of patients who made user errors had decreased to 29% (p < 0.001). Eighty-five percent of the patients reported that they used their blood glucose results to adjust medication, exercise or meals. Fifty-one percent of the patients reported a greater trust in their measurements after the second visit. Eighty percent of patients wished to have their measurements assessed yearly. Of these patients, 83% preferred to have the assessment done at the community pharmacy. CONCLUSION: A community pharmacy-based quality assessment procedure of patients' self monitoring of blood glucose significantly reduced the number of user errors. The analytical quality of the patients' measurements was good and did not improve further during the study. The high analytical quality might be explained by a selection bias of participating patients. Patients also reported increased confidence in their blood glucose measurements after their measurements had been assessed at the pharmacy.

Results and feasibility of an external quality assessment scheme for self-monitoring of blood glucose.

BACKGROUND: The analytical quality of self-monitoring of blood glucose (SMBG) is not satisfactory, and the need for standardized control routines for SMBG has been underscored. The objective of this study was to investigate whether an external quality assessment scheme (EQAS) designed for office laboratories could improve the quality of SMBG measurements. METHODS: From October 2001 through March 2004, we conducted 6 glucose surveys for diabetes patients and coordinated them with an EQAS for office laboratories. Patients received 2 control samples by post twice a year. They measured each control sample in duplicate in accordance with written instructions, returned the results, and received an assessment of their analytical performance. Participants who got a poor evaluation were followed up by phone and were offered guidance. RESULTS: Participating in an EQA program over a period of 3 years decreased the percentage of poor results among diabetes patients significantly, from 11.2% to 1.9% in the first and last surveys, respectively. Between-participant CVs improved from 5.5% to 3.7% and were comparable to results from office laboratories. It was difficult to sort out factors contributing to quality improvement. CONCLUSIONS: Implementing a traditional EQAS among diabetes patients may improve the analytical quality of SMBG and could be convenient for motivated patients. Further evaluation of the clinical usefulness of implementing such a program is needed, however, and costs as well as limitations of current EQAS for glucose in general should be taken into account.

Instruments for self-monitoring of blood glucose: comparisons of testing quality achieved by patients and a technician.

BACKGROUND: Instruments for self-monitoring of blood glucose (SMBG) are increasingly used by patients with diabetes. The analytical quality of meters in routine use is poorly characterized. METHODS: We compared SMBG performance achieved by patients and by a medical laboratory technician. Imprecision was calculated from duplicate measurements, and deviation as the difference between the first measurement and the mean of duplicate laboratory-method results (calibrated with NIST material). Analytical quality for five groups of SMBG instruments was compared with quality specifications for BG measurements. All participants completed a questionnaire assessing both SMBG training and use of the meters. RESULTS: We recruited 159 SMBG users from a hospital outpatient clinic and 263 others from 65 randomly selected general practices (total of 422). Most (two thirds) used insulin. CVs for the five meter types were 7%, 11%, 18%, 18%, and 20% in the hands of patients and 2.5-5.9% for the technician. For three of five meter types, patients' BG measurements had larger deviations from the laboratory results than did the technician's results. The technician's performance could not predict the patients'. No instrument when used by patients (but two operated by the technician) met published quality specifications. The analytical quality of patients' results was not related to whether they had chosen the instruments on advice from healthcare personnel (one-third of patients), were only self-educated in SMBG (50%), or performed SMBG fewer than seven times/week (62%). CONCLUSIONS: The analytical quality of SMBG among patients was poorer than, and could not be predicted from, the performance of the meters in the hands of a technician. We suggest that new instruments be tested in the hands of patients who are trained on meter use in a routine way.