Test Strip Lot Number Is Uploaded Onto the Mter

• Journal List
• J Diabetes Sci Technol
• v.6(v); 2012 Sep
• PMC3570841

J Diabetes Sci Technol. 2012 Sep; 6(v): 1076–1086.

Lot-to-Lot Variability of Exam Strips and Accuracy Assessment of Systems for Self-Monitoring of Blood Glucose according to ISO 15197

Annette Baumstark, Ph.D., Stefan Pleus, M.S., Christina Schmid, Ph.D., Manuela Link, M.E., Cornelia Haug, M.D., and Guido Freckmann, M.D.

Abstract

Groundwork

Authentic and reliable blood glucose (BG) measurements crave that unlike exam strip lots of the same BG monitoring system provide comparable measurement results. Only a small-scale number of studies addressing this question accept been published.

Methods

In this written report, 4 test strip lots for each of v different BG systems [Accu-Chek® Aviva (system A), FreeStyle Low-cal® (organisation B), GlucoCheck Xl (system C), Pura™/mylife™ Pura (organization D), and OneTouch® Verio™ Pro (system E)] were evaluated with procedures according to DIN EN ISO 15197:2003. The BG system measurement results were compared with the manufacturer's measurement procedure (glucose oxidase or hexokinase method). Relative bias according to Bland and Altman and organization accuracy co-ordinate to ISO 15197 were analyzed. A BG system consists of the BG meter itself and the test strips.

Results

The maximum lot-to-lot difference between any two of the iv evaluated test strip lots per BG system was ane.0% for system E, 2.1% for organisation A, three.1% for arrangement C, 6.9% for organisation B, and 13.0% for system D. Only two systems (systems A and B) fulfill the criteria of DIN EN ISO 15197:2003 with each exam strip lot.

Conclusions

Considerable lot-to-lot variability between test strip lots of the aforementioned BG system was plant. These variations add to other sources of inaccuracy with the specific BG system. Manufacturers should regularly and effectively check the accuracy of their BG meters and test strips even between dissimilar exam strip lots to minimize take a chance of faux treatment decisions.

Keywords: blood glucose monitoring systems, Conformité Européenne marking, DIN EN ISO 15197:2003, lot-to-lot variability, self-monitoring of blood glucose, system accuracy

Introduction

Self-monitoring of blood glucose (SMBG) is a widely accustomed instrument in modern diabetes direction that allows for tight blood glucose (BG) control in diabetes patients.^1–four Thus SMBG is recommended for all patients with diabetes, especially for patients who suit their insulin doses based on BG measurement results.^2,5–7

The accuracy of a BG measurement, eastward.g., as defined by the international standard DIN EN ISO 15197:2003,^viii is imperative for the issue's reliability and utility for BG control. Compliance with DIN EN ISO 15197:2003 is one footstep in the Conformité Européenne (CE)-marking process. The CE mark is a prerequisite for all devices, including BG meters, that are distributed in the European Marriage market. With the application of the CE mark on a BG meter, the manufacturer declares that the device meets the European Union requirements and that all required conformity evaluation procedures were performed in cooperation with a nationally accredited notified torso. This approval procedure for medical devices in Europe is different to the approval process of drugs by the European Medicines Agency or to the blessing procedure for medical devices past the Nutrient and Drug Administration in the The states.

Measurement results obtained with a given BG meter might vary when different exam strip lots are used. This lot-to-lot variability is addressed in the current draft revision of International System of Standardization 15197 (ISO/DIS 15197, expected to be published in 2012),^nine which requires the evaluation of three different examination strip lots per BG system; each individual lot has to fulfill the requirements of this standard.

Lot-to-lot variability was evaluated in some studies,^10–12 but simply a few studies extensively investigated this topic.^13–15

In order to evaluate the bear upon of lot-to-lot variability for five dissimilar BG systems, this written report investigated (i) the bias between four examination strip lots of each BG organisation and (ii) the organization accuracy for each test strip lot (then, in total, the system accuracy for twenty test strip lots), using data obtained following the standardized procedures of DIN EN ISO 15197:2003, ensuring comparability of results.

Materials and Methods

This study was performed between 2010 and 2011 at the Institut für Diabetes-Technologie GmbH in Ulm, Germany, in compliance with the High german Medical Devices Act. The Ulm Academy ideals commission reviewed and approved the study protocol, and the competent authority was notified. Signed informed consent forms were provided past all participants. The study procedures are identical to those used in another report performed at the same study site (meet Freckmann and colleagues^sixteen in this issue) and described in detail in DIN EN ISO 15197:2003.^viii Deviations from these procedures are described here.

Blood Glucose Systems

In this study's context, a BG arrangement consists of one type of BG meter and the test strips labeled for use with this meter. The five evaluated BG systems and the four examination strip lots used with each BG system are listed in Tabular array 1 . They are all current, CE-marked systems. The first examination strip lot for each BG system was also assessed in another report at the aforementioned written report site, which focused on system accurateness of a wide diverseness of BG systems (meet Freckmann and colleagues¹⁶ in this outcome). The 5 systems have been selected in order to compare multiple test strip lots of systems from established and new manufacturers. A benchmark was marketplace availability of 4 lots. Also, the availability of a CE mark and the availability of BG meters and test strips in the required quantities as well as the availability of several lots in a divers fourth dimension frame for an ISO assessment have been the fundamental prerequisites. For a BG system to be included in the evaluation, it had to be labeled for SMBG usage. In deviation to DIN EN ISO 15197:2003, exam strips were taken from at least 8 (instead of 10) unlike packages or vials, which were changed after approximately 10 subjects.

Table 1

Blood Glucose Systems (Listed Alphabetically) and Test Strip Lots Evaluated ^a

BG organization	Manufacturer	Reference method	Scale	Enzymatic test strip reaction	Written report appointment	Test strip lot	Examination strip lot number	Decease appointment (test strip)
Accu-Chek® Aviva (organization A)	Roche Diagnostics GmbH, Federal republic of germany	HK	Plasma	GDH	xi/2010–02/2011	A1	490018	11/2011
					04/2011–05/2011	A2	490101	04/2012
					09/2011	A3	490270	09/2012
					09/2011	A4	490310	10/2012
FreeStyle Lite® (organisation B)	Abbott Diabetes Care Inc., United states	GOx	Plasma	GDH	06/2010–07/2010	B1	1055813	08/2011
					06/2010–07/2010	B2	1008533	09/2011
					10/2011–11/2011	B3	1073832	02/2012
					10/2011–11/2011	B4	1170870	01/2013
GlucoCheck Xl (system C)	aktivmed GmbH, Germany	GOx	Plasma	GDH	04/2011–05/2011	C1	TD10J114-B0E	04/2012
					04/2011–05/2011	C2	TD10K109-B0E	05/2012
					04/2011–05/2011	C3	TD10K309-B0E	05/2012
					04/2011–05/2011	C4	TD10K109-B0D	05/2012
Pura/mylife Pura (system D)	Bionime Corporation, Taiwan	HK	Plasma	GOx	03/2010	D1	1196232	05/2011
					09/2011	D2	1199184	09/2011
					09/2011	D3	1103298	03/2012
					10/2011–11/2011	D4	1106012	05/2012
OneTouch® Verio™ Pro (system Due east)	LifeScan Europe, Switzerland	GOx	Plasma	GDH	02/2011–03/2011	E1	3078405	01/2012
					04/2011–05/2011	E2	3083731	01/2012
					04/2011–05/2011	E3	3083133	01/2012
					04/2011–05/2011	E4	3083136	01/2012

Subjects and Test Procedure

Subjects (≥18 years old) with diabetes mellitus type i and type 2 as well equally subjects without diabetes were included. Exclusion and study interruption criteria for subjects are identical to those described past Freckmann and colleagues^sixteen (this issue). For each test strip lot of the BG systems evaluated, blood samples of at least 100 subjects were used. Two individual BG meters were used for each test strip lot co-ordinate to section seven.3.2 of DIN EN ISO 15197:2003. In instance of failure, BG meters were replaced. Measurements were performed on at to the lowest degree 10 days for each exam strip lot, and suitable control procedures were performed daily prior to the test procedure. The tests were performed past clinical personnel well trained to the treatment of the BG systems, the manufacturer'southward device labeling, the condom practices, and the exam protocol. The tests were performed in a laboratory setting with controlled room temperature (23 ± five °C) and humidity (co-ordinate to the manufacturers' specifications).

Reference Measurement

Reference measurements were performed with the following two methods for all BG systems: glucose oxidase (GOx) [YSI 2300 STAT Plus™ glucose analyzer, YSI Life Sciences, Yellow Springs, OH; measurements were performed at the study site] and hexokinase (HK) [Hitachi 917 (from March 2010 to Baronial 2010)/cobas® 6000 c501 (since August 2010), Roche Diagnostics GmbH, Mannheim, Deutschland; measurements were performed at a Deutsche Akkreditierungsstelle-accredited scale laboratory of Roche Diagnostics GmbH, Mannheim, Germany]. Internal and external quality control measurements were performed as described past Freckmann and colleagues^xvi (this issue).

The measurement results of each exam strip lot were compared confronting the measurement results of the manufacturer's measurement procedure, i.e., the reference method specified in the device labeling.

The BG meters displayed plasma equivalent BG values in mg/dl or mmol/liter. Reference measurements were performed from whole blood, which was hemolyzed and deproteinized for the HK method. Both reference measurement procedures showed whole blood BG values in mg/dl, from which plasma equivalent values were calculated for comparison with the test strip lot results. Measurement results obtained with the GOx method were converted from whole blood BG values to plasma equivalent BG values as follows:

plasma equivalent BG value (in mg/dl) = whole claret BG value (in mg/dl) / [ane - (0.0024 × hematocrit value [in %])].¹⁷

Results from the HK method were converted using a constant conversion factor:

plasma equivalent BG value (in mg/dl) = 1.11 × whole blood BG value (in mg/dl).

Test Protocol

DIN EN ISO 15197:2003 specifies the distribution of theblood samples into different BG concentration categories ( Table ii ). The limits of these categories were slightly modified considering they are not conspicuously divers and differ between the English and the German version of the standard. Additionally, the distribution of blood samples is based on the mean BG values obtained with the reference method, thus deviating from the standard, which states that distribution shall exist based on the results determined with the BG arrangement. The current draft revision of ISO 15197 demands distribution based on the reference BG values.

Table 2

Distribution of Glucose Concentration according to EN ISO 15197 with Slight Modifications

Percentage of samples	Glucose concentration mmol/liter (mg/dl)
5	<two.8 (≈ <50)
15	≥2.eight–<iv.35 (≈ ≥50–<80)
20	≥4.35–<6.vii(≈ ≥lxxx–<120)
30	≥vi.7–<11.15 (≈ ≥120–<200)
15	≥11.15–<xvi.65 (≈ ≥200–<300)
10	≥16.65–<22.2 (≈ ≥300–<400)
5	≥22.ii (≈ ≥400)

For BG concentrations between fifty and 400 mg/dl, just native, unaltered whole claret samples were used.If numbers of unaltered blood samples with BG concentrations <50 and >400 mg/dl were insufficient, modified claret samples were prepared, either by glycolysis or glucose supplementation. A detailed description is available from Freckmann and colleagues.¹⁶ These preparation procedures did non ensure constant oxygen concentrations of the blood samples, which might affect BG systems with GOx-based examination strip chemistry. The merely BG arrangement with GOx test strip chemical science evaluated in this written report is the Pura™/mylife™ Pura. No correction or exclusion of modified claret samples was performed because oxygen interference is not mentioned in the manufacturer's labeling.

Fresh capillary whole blood samples were collected from at least 100 subjects by puncturing the peel at the fingertips. Hematocrit values of these samples had to be within 30% and 55%. For the conclusion of the hematocrit, capillary whole blood was collected in heparinized capillaries (double exam). After centrifugation, the hematocrit was read on an alignment chart.

Sampling sequence steps were as follows (more than detailed steps are described by Freckmann and colleagues^xvi):

1. Sample collection for the 2 reference measurement procedures.

2. BG measurements with two test strip lots of the same or different BG systems, two meters per organisation.

3. Sample collection for the 2 reference measurement procedures.

Before measurements with each test strip lot and before each sample collection for each reference measurement process, residual blood was wiped off the fingertip. Ordinarily, the aforementioned drop of blood was used for measurements with the two BG meters of the respective BG arrangement.

The drift betwixt the get-go and 2d reference measurement result must not exceed four mg/dl at BG concentrations ≤100 mg/dl or 4% at BG concentrations >100 mg/dl.

A total of eight measurement results were excluded due to deviation from exam protocol, and 1 sampling sequence was repeated because of a technical error.

The statistical assay of each examination strip lot of each BG system included 200 results from 100 subjects, which were compared with the reference measurement issue.

Statistical Analyses

All statistical analyses were performed at the study site. Calculations were performed in mmol/liter with a unit conversion equally follows:

BG value in mmol/liter = 1/eighteen.02 × BG value in mg/dl.

The relative bias (%) of the measurement results of each examination strip lot was calculated according to Bland and Altman¹⁸ using the formula

1 northward ∑ n two × ( B G - r eastward f e r e northward c eastward ) ( B G + r e f e r e n c eastward ) × 100 ,

where BG is a single BG measurement event obtained with one specific exam strip lot, reference is the mean value of the reference measurements before and subsequently the BG measurement with this test strip lot, and n is the number of all BG measurement results obtained with this test strip lot. For calculation of each examination strip lot'due south relative bias, all included measurement results were analyzed. The relative bias is shown with 95% limits of understanding (≈ ±i.96 × standard deviation).

The accuracy of each of the 20 test strip lots' (four test strip lots from 5 BG systems) results was evaluated by comparing with the respective mean value of the reference measurement results (GOx method or HK method) obtained immediately earlier and later the measurements with the test strip lot. According to DIN EN ISO 15197:2003, at BG concentrations <75 mg/dl, the relative number of the examination strip lot'south results within ±15, ±ten, and ±5 mg/dl and, at BG concentrations ≥75 mg/dl, the relative number of the examination strip lot's results within ±20%, ±xv%, ±10% and ±v% of the reference were calculated. In order to appraise the overall accuracy of a specific examination strip lot, the number of this examination strip lot'south results within ±xv mg/dl at BG concentrations <75 mg/dl was added to the number of results within ±20% at BG concentrations ≥75 mg/dl and divided by the number of all measurement results obtained with this test strip lot. In addition, the accuracy of the 20 test strip lots' results was evaluated using the limits of the current typhoon revision of ISO 15197. At BG concentrations <100 mg/dl, the relative number of system results inside ±15, ±10, and ±5 mg/dl and, at BG concentrations ≥100 mg/dl, the relative number of system results inside ±fifteen%, ±10%, and ±five% of the reference measurement were calculated. Similar to the evaluation according to DIN EN ISO 15197:2003, the number of this exam strip lot'due south results within ±15 mg/dl at BG concentrations <100 mg/dl was added to the number of results within ±15% at BG concentrations ≥100 mg/dl and divided past the number of all measurement results obtained with this test strip lot.

To illustrate the accuracy of each exam strip lot co-ordinate to DIN EN ISO 15197:2003, the understanding between each measurement result and the mean reference issue of the manufacturer's measurement procedure was plotted in a difference plot for each test strip lot separately.

The difference plot shows the deviation of unmarried measure-ment results of the specific examination strip lot from the true result (reference value). It shows both random and systematic deviations, which reverberate the total measuring mistake of the examination strip lot.

Results

Table 3 shows the relative bias and limits of agreement for each test strip lot separately and the boilerplate relative bias of the iv examination strip lots with each BG system.

Tabular array three

Relative Bias and Limits of Agreement according to Bland and Altman ^a

BG system	Reference method	Average relative bias (%)	Examination strip lot	Relative bias (%)	Lower limit of agreement (%)	Upper limit of understanding (%)
Accu-Chek Aviva (arrangement A)	HK	-0.4	A1	-0.7	-11.8	x.5
			A2	1.1	-8.iii	10.5
			A3	-i.0	-x.v	viii.5
			A4	-0.nine	-10.0	8.3
FreeStyle Lite (system B)	GOx	-four.0	B1	-0.viii	-7.6	5.ix
			B2	-half dozen.0	-22.0	ten.1
			B3	-1.4	-eleven.8	ix.0
			B4	-7.vii	-20.2	4.8
GlucoCheck XL (system C)	GOx	2.8	C1	4.6	-13.3	22.4
			C2	2.seven	-sixteen.ix	22.4
			C3	ii.3	-twenty.8	25.4
			C4	i.v	-17.7	20.vi
Pura/mylife Pura (system D)	HK	-9.0	D1	-6.vii	-19.5	6.1
			D2	-17.3	-33.9	-0.vii
			D3	-4.3	-16.4	7.8
			D4	-7.half-dozen	-19.2	4.0
OneTouch Verio Pro (arrangement E)	GOx	8.8	E1	8.5	-4.2	21.two
			E2	9.five	-iv.0	22.9
			E3	viii.vii	-3.0	twenty.four
			E4	8.5	-5.0	22.0

The relative bias of the single exam strip lots ranged from -17.3% to +9.5% ( Figure ane ). The maximum departure in relative bias between any 2 of the 4 examination strip lots of a BG system was 1.0% for organization E, 2.1% for system A, three.1% for system C, 6.9% for system B, and 13.0% for system D. Averaged over all four test strip lots, the smallest relative bias was achieved by system A, with a relative bias of -0.4%, followed by system C (+two.8%), system B (-four.0%), system Eastward (+8.eight%), and organisation D (-9.0%).

Relative bias according to Bland and Altman for five BG systems, four examination strip lots per organization. Antennae illustrate 95% limits of understanding. For the calculation of the relative bias of each system, information of 200 blood samples (BG concentrations <50 to >400 mg/dl) were included.

The per centum of BG measurement results within different departure ranges according to DIN EN ISO 15197:2003 and according to the current draft revision of ISO 15197 are shown in Table 4 . In addition to these percentages, the overall accurateness assessments, including all BG measurement results, are displayed.

Table four

Organization Accurateness Results with Accuracy Limits co-ordinate to DIN EN ISO 15197:2003 and the Electric current Draft Revision of ISO 15197

			DIN EN ISO 15197:2003									Electric current draft revision of ISO 15197
					BG concentration <75 mg/dl			BG concentration ≥75 mg/dl						BG concentration <100 mg/dl			BG concentration ≥100 mg/dl
BG system	Refer-ence method a	Exam strip lot	Within accuracy limits (±15 mg/dl and ±20%)		±15 mg/dl	±x mg/dl	±5 mg/dl	±20%	±15%	±10%	±5%	Within accurateness limits (±15 mg/dl and ±15%)		±fifteen mg/dl	±10 mg/dl	±5 mg/dl	±fifteen%	±10%	±5%
			n	%	%	%	%	%	%	%	%	north	%	%	%	%	%	%	%
Accu-Chek Aviva (system A)	HK	A1	(200/200)	100.0	100	100	87	100	99	91	64	(198/200)	99.0	100	97	80	99	91	64
		A2	(200/200)	100.0	100	98	83	100	100	96	68	(200/200)	100.0	100	98	78	100	96	68
		A3	(200/200)	100.0	100	100	97	100	100	96	68	(200/200)	100.0	100	100	95	100	96	64
		A4	(200/200)	100.0	100	100	92	100	100	99	71	(200/200)	100.0	100	100	92	100	99	68
FreeStyle Lite (system B)	GOx	B1	(200/200)	100.0	100	100	95	100	100	100	86	(200/200)	100.0	100	100	93	100	100	86
		B2	(199/200)	99.5	100	84	58	99	86	66	45	(179/200)	89.5	100	86	59	85	63	43
		B3	(200/200)	100.0	100	100	80	100	100	94	62	(200/200)	100.0	100	100	71	100	94	64
		B4	(200/200)	100.0	100	88	65	100	98	80	34	(196/200)	98.0	100	91	66	97	78	31
GlucoCheck XL (arrangement C)	GOx	C1	(191/200)	95.5	98	95	63	95	89	67	twoscore	(182/200)	91.0	97	92	58	88	65	40
		C2	(191/200)	95.5	93	fourscore	lx	96	91	77	46	(183/200)	91.v	92	77	52	91	78	47
		C3	(187/200)	93.5	93	88	68	94	88	77	38	(177/200)	88.5	90	87	61	88	75	38
		C4	(189/200)	94.5	88	83	58	96	91	80	52	(182/200)	91.0	ninety	85	53	91	80	53
Pura/mylife Pura (organization D)	HK	D1	(200/200)	100.0	100	92	55	100	100	75	thirty	(200/200)	100.0	100	95	48	100	74	thirty
		D2	(174/200)	87.0	82	29	0	88	43	19	10	(105/200)	52.5	77	21	0	44	21	11
		D3	(199/200)	99.5	100	97	79	99	98	83	forty	(197/200)	98.5	100	98	79	98	81	37
		D4	(199/200)	99.five	100	100	78	99	89	64	29	(183/200)	91.v	100	100	72	88	61	27
OneTouch Verio Pro (system E)	GOx	E1	(193/200)	96.5	93	63	xx	98	90	70	38	(183/200)	91.five	88	53	21	93	75	40
		E2	(188/200)	94.0	85	53	eighteen	96	fourscore	63	32	(167/200)	83.5	79	41	14	85	68	35
		E3	(193/200)	96.5	95	68	28	97	91	62	28	(186/200)	93.0	89	55	20	94	66	31
		E4	(190/200)	95.0	85	63	18	98	87	66	38	(175/200)	87.5	84	52	13	89	71	42

Figures ii–4 show the agreement between the BG measurements results and the mean reference result (manufacturer'due south measurement procedure) for each examination strip lot of each BG system in difference plots. Because single test strip lots, only system A and organization B fulfilled the requirements stated in DIN EN ISO 15197:2003 with all four test strip lots: 100.0% of system A measurements were within the 2003 limits and 99.0% to 100.0% inside the draft limits, and organisation B had 99.five% to 100.0% of the measurements within the 2003 limits and 89.five% to 100.0% within the typhoon limits. For organization C, two of four test strip lots fulfilled the 2003 requirements (93.5% to 95.5%) and 88.5% to 91.5% of the measurements were within the draft limits. Organization D test strip lots showed 87.0% to 100.0% of measurements inside the accurateness limits of the 2003 standard, thus 3 of 4 test strip lots fulfilled the requirements; 52.5% to 100.0% of the measurements were within the draft limits. For organization E, three of 4 test strip lots fulfilled the 2003 requirements (94.0% to 96.5%), with 83.v% to 93.0% of measurements within the limits of the current draft revision of ISO 15197.

Deviation plots for FreeStyle Low-cal® and Accu-Chek® Aviva BG systems, 4 test strip lots per arrangement. Solid lines illustrate the zilch line and the system accuracy limits of EN ISO 15197. Dashed lines show system accuracy limits of the current draft revision of ISO 15197. ○, test strip lot one; □, test strip lot 2; +, exam strip lot 3; ×, test strip lot 4.

Difference plots for OneTouch® Verio Pro BG system, four exam strip lots per system. Solid lines illustrate the nix line and the system accuracy limits of EN ISO 15197. Dashed lines show system accurateness limits of the electric current typhoon revision of ISO 15197. ○, test strip lot i; □, test strip lot 2; +, exam strip lot 3; ×, test strip lot 4.

Difference plots for mylife™ Pura™ and GlucoCheck Xl BG systems, four exam strip lots per system. Solid lines illustrate the zero line and the organization accuracy limits of EN ISO 15197. Dashed lines testify system accuracy limits of the current draft revision of ISO 15197. ○, test strip lot 1; □, examination strip lot 2; +, test strip lot three; ×, test strip lot 4.

Discussion

An of import aspect of the measurement accurateness is the lot-to-lot variability betwixt multiple test strip lots used with i BG organization. Therefore, data generated in an accuracy assay according to EN ISO 15197 and thus including measurement results ranging from <50 to >400 mg/dl was used in order to investigate lot-to-lot variability of five BG systems with four test strip lots each. The requirements of DIN EN ISO 15197:2003 were fulfilled by all evaluated test strip lots separately for merely 2 of the tested BG systems. Only 1 system had at to the lowest degree 95% of the measurements within the stricter accurateness limits of the current draft revision of ISO 15197 with each test strip lot.

In this report, for the evaluation of the measurement accurateness, besides analysis of the system accuracy according to ISO 15197, the relative bias according to Bland and Altman was taken into account. Considerably varying bias (>five%) betwixt the evaluated exam strip lots was institute in 2 out of five BG systems.

This result is comparable to results from other studies that investigated between-lot variations and also found marked lot-to-lot variability in bias for some BG systems.^13–15 Constant bias over multiple test strip lots may not necessarily exist an outcome, equally patients may, over time, accommodate to a stable given bias, whereas strongly varying bias might have a negative result on BG command, as accommodation is non possible.

This investigation considered a BG concentration interval from <50 to >400 mg/dl, without separating into the unlike clinically relevant concentration intervals, i.e., hypoglycemic, euglycemic, and hyperglycemic ranges as well every bit intervals specific to certain types of diabetes therapy. Therefore, the clinical impact of the direction of a measurement bias in different intervals, e.g., negative bias at hypoglycemic concentrations versus positive bias at hypoglycemic concentrations, was not examined.

The lot-to-lot variability adds to other sources of inaccuracy of a specific BG system. These sources include differences in the manufacturer's measurement procedure,^nineteen manufacturer-specific plasma conversion factors, but also handling errors by the users.^20–23 Every bit another possible source of inaccuracy, nosotros observed variability betwixt different test strip vials within one lot.

Several studies showed that accuracy of BG measure-ments vary largely between unlike BG systems.^{thirteen,24–26} It is worth mentioning that the extent of some lot-to-lot variability observed in this study was comparable to the variations observed between different BG systems. These variations hamper the accomplishment of strict glycemic goals, e.chiliad., every bit required in patients with gestational diabetes or type 1 diabetes, because neither the patients nor the wellness intendance professionals are aware of the magnitude or even the existence of these variations.

In summary, this written report showed that there are considerable differences in the measurement quality of different exam strip lots of the same BG system. These differences probably have an bear upon on the reliability of the BG measurements and, subsequently, on therapeutic decisions. The clinical impact of lot-to-lot differences of examination strips has not been studied thoroughly then far. Before being introduced to the market, BG systems have to be tested in a premarket blessing, i.e., if they fulfill certain requirements. All the same, once being commercially bachelor, there are no mandatory tests, eastward.thousand., for accuracy evaluation of exam strip lots from routine production.

As inaccurate BG systems bear the risk of erroneous therapeutic decisions past the patient and/or health care professional and subsequent possible astringent health injury, lot-to-lot variability of examination strips should exist evaluated by manufacturers or by an independent specialized institution.

Acknowledgments

We give thanks Prof. Dr. Theodor Koschinsky for his valuable input in information evaluation and word. We also thank Prof. Dr. Lutz Heinemann for contributing his scientific expertise to the discussion.

Glossary

Abbreviations

(BG)	blood glucose
(CE)	Conformité Européenne
(GOx)	glucose oxidase
(ISO)	International Arrangement for Standardization
(SMBG)	self-monitoring of blood glucose

Funding

This study was funded by a grant from Roche Diagnostics GmbH, Mannheim, Germany.

Disclosures

Guido Freckmann received speaker's honoraria and refunding of traveling expenses for congress participation from Roche Diagnostics GmbH, Mannheim, Germany, the sponsor of this study, and from Berlin-Chemie AG, Berlin, Germany.

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Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3570841/

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