Why Do Different Fingers Have Different Glucose Readings

Diabetes Care. 2011 Mar; 34(3): 556–560.

Self-Monitoring of Blood Glucose: The Utilize of the First or the 2nd Drib of Blood

Johanna Hortensius, RN,^ane Robbert J. Slingerland, PHD,^two Nanne Kleefstra, MD, PHD,^{1, 3, iv} Susan J.J. Logtenberg, Doctor, PHD,^ane Klaas H. Groenier, PHD,⁵ Sebastiaan T. Houweling, Physician, PHD,^{3, 6} and Henk J.G. Bilo, MD, PHD, FCRP^{one, 4}

Johanna Hortensius

^aneDiabetes Centre, Isala Clinics, Zwolle, holland

Robbert J. Slingerland

²Department of Clinical Chemistry, Isala Clinics, Zwolle, the Netherlands

Nanne Kleefstra

¹Diabetes Centre, Isala Clinics, Zwolle, the Netherlands

^threeMedical Research Group, Langerhans, the Netherlands

⁴Department of Internal Medicine, University Medical Middle, Groningen, the Netherlands

Susan J.J. Logtenberg

¹Diabetes Center, Isala Clinics, Zwolle, kingdom of the netherlands

Klaas H. Groenier

⁵Department of General Do, University of Groningen, Groningen, the netherlands

Sebastiaan T. Houweling

ⁱⁱⁱMedical Research Group, Langerhans, the Netherlands

⁶General Exercise Sleeuwijk, Sleeuwijk, the Netherlands

Henk J.G. Bilo

^aneDiabetes Centre, Isala Clinics, Zwolle, the netherlands

^fourSection of Internal Medicine, University Medical Center, Groningen, holland

Received 2010 Sep 1; Accepted 2010 Dec 31.

Abstract

OBJECTIVE

In that location is no full general agreement regarding the use of the first or 2nd driblet of blood for glucose monitoring. This study investigated whether capillary glucose concentrations, as measured in the first and 2d drops of blood, differed ≥x% compared with a control glucose concentration in different situations.

Enquiry Pattern AND METHODS

Capillary glucose concentrations were measured in ii consecutive drops of blood in the following circumstances in 123 patients with diabetes: without washing hands, later exposing the hands to fruit, after washing the fruit-exposed hands, and during awarding of different amounts of external force per unit area around the finger. The results were compared with control measurements.

RESULTS

Not washing hands led to a difference in glucose concentration of ≥10% in the first and in the second drops of blood in 11% and iv% of the participants, respectively. In fruit-exposed fingers, these differences were found in 88% and xi% of the participants, respectively. Different external pressures led to ≥10% differences in glucose concentrations in 5–thirteen% of the participants.

CONCLUSIONS

We recommend washing the hands with lather and h2o, drying them, and using the first drib of claret for cocky-monitoring of claret glucose. If washing hands is not possible, and they are not visibly soiled or exposed to a sugar-containing product, it is acceptable to utilize the second drop of blood afterwards wiping away the showtime drop. External force per unit area may lead to unreliable readings.

Self-monitoring of blood glucose (SMBG) is an of import part of diabetes care. The purpose of SMBG is to provide a timely and reliable assessment of blood glucose concentrations in an individual in order to exist able to make acceptable decisions in relation to diet, do, and medication (1,2).

There are several aspects concerning SMBG that need attention. For instance, there is no general understanding regarding the use of the outset or the 2d driblet of claret for glucose monitoring. In the Netherlands, there are three different recommendations. Firstly, using the first drop of blood after washing the hands with soap and water or after disinfecting the finger and waiting until the finger is dry (3). Secondly, using the first driblet of blood later on washing the hands with soap and h2o and using the second driblet of claret when the patient has non washed the hands (4). Thirdly, always using the second drib of claret after washing the hands with soap and water (5). Furthermore, in one of these recommendations, patients are advised not to squeeze the finger to obtain a drop of blood equally this could potentially influence the blood glucose concentration (3).

To address the questions raised by these different recommendations, we conducted a study with a cantankerous-sectional design to investigate whether capillary glucose concentrations, equally measured in the first and 2d drops of claret, differed x% or more compared with a command capillary glucose concentration, in the following situations:

1. without washing hands

2. after handling fruit

3. afterwards washing the fruit-exposed fingers

4. during the application of unlike amounts of external force per unit area around the finger (squeezing)

Enquiry DESIGN AND METHODS

Patients were recruited from the outpatient dispensary of the Department of Internal Medicine of the Isala Clinics in Zwolle, the Netherlands. Eligibility criteria were a diagnosis of blazon i or type ii diabetes, treated with insulin, SMBG, and historic period >eighteen years.

Eligible patients received a letter with information most the study and an invitation to participate at their adjacent outpatient clinic visit. Recruitment took place between September 2009 and February 2010. Blessing for the written report was obtained from the local medical ethics commission. All patients gave written informed consent.

Information on glycemic control and BMI were collected from hospital records, and the hematocrit value was assessed.

Intervention

Capillary glucose concentrations for two consecutive drops of claret were measured in four unlike circumstances: 1) without washing hands, 2) after handling with fruit, three) after washing the fruit-exposed hands, and iv) during the application of different amounts of force per unit area around the finger. All capillary claret glucose concentrations were adamant without squeezing ("milking") except in the intervention where this aspect was investigated. All glucose measurements were nonfasting and were performed at times depending on scheduled outpatient clinic visit.

Description of the interventions

Intervention 1: not washing easily.

The participant arrived at the research setting and did non launder the hands prior to the first finger puncture. The capillary blood glucose concentrations were adamant from the first and second drops of blood, and the puncture site was wiped past a tissue in between obtaining the first and second drops.

Intervention 2: finger exposed to fruit.

The participant washed the hands with soap and water and stale them. The participant and then handled either an apple tree or a assistant. This fruit is mostly used in the Dutch population. The participant either cut part of an apple (jonagold) into 3 pieces with a knife and bankrupt the pieces into 2 smaller pieces with the easily, or peeled a piece of a ripe assistant and broke the piece into two smaller pieces with the hands. After handling the fruit, the capillary blood glucose concentrations were determined in the commencement and second drops of blood, and the finger was wiped off with a tissue in between obtaining the two drops.

Intervention 3: washing the fruit-exposed finger.

As in intervention 2, the participant'southward other forefinger was exposed to a slice of fruit. The participant then washed the hands with lather and water and dried them. The tests were repeated.

Intervention iv: different external pressures.

The participant washed the hands with lather and water and dried them. The cuff of the hand blood pressure meter was put effectually the middle phalanx of the middle finger. The pressure was increased to 240 mmHg. Immediately, a finger puncture was performed, and the capillary glucose concentration was adamant in the first and in the second drops of blood, once more wiping the finger with a tissue in between the two drops. Thereafter, the finger cuff was put around the middle phalanx of the ring finger of the same hand. The cuff was inflated to xl mmHg. A finger puncture was performed later on one min to achieve venous stasis, and the tests were repeated.

Control measurement

The patient washed the easily with soap and h2o and dried them. A finger puncture was performed. A mean capillary claret glucose concentration was obtained by averaging the result obtained from the first and second drops of claret (the finger was wiped off later the showtime driblet was obtained). This upshot was used equally the control after instrument combined with strip and performance bias were excluded. A separate control was calculated for each of interventions 1, ii, and 3 with the command for intervention 1 existence performed after the intervention, and the control for intervention 3 also being used for intervention 4.

Time interval during measurements

Capillary glucose measurements were performed directly post-obit the finger puncture with a maximum delay of ninety south between measurements.

Measuring equipment

All capillary glucose values were determined with the Accu-Chek Compact plus meter with plasma-calibrated exam strips (Roche, Almere, the Netherlands). A Speidel and Keller hand blood pressure meter was used to achieve different external pressures. The regular gage was replaced by a neonatal cuff. One of two available sizes was used depending on the thickness of the finger (Philips, M1866A neonatal disposable cuff #one and M1868A neonatal dispensable cuff #ii). The meter was calibrated prior to the outset of the study likewise as halfway through the study. No significant changes were observed.

Statistical analyses

Descriptive statistics include mean (SD) and median (interquartile range). All information were reviewed for normality using Q-Q plots, and parametric and nonparametric tests were used every bit appropriate. The Wilcoxon signed rank exam was used to test for differences in glucose concentrations. Bland-Altman plots were produced and intraclass correlation coefficients were calculated for assessing agreement between measurements and for the reliability of the control measurement (6).

A difference of ≥10% between control and intervention values or a divergence of 0.82 mmol/50 in the case of a glucose concentration <4.two mmol/Fifty was considered to be clinically relevant. An intervention was considered to lead to reliable readings when 95% of the readings were within x% differences. The 10% is based on the external quality cess scheme, the quality mark for self-examination glucose meters, assessing belittling quality and technical quality (7). The full commanded error in the quality mark is ix.four%, based on the inter- and intraperson variation concept of Fraser and Peterson. (eight).

Clarke error grids were used to investigate how often the outcome would lead to a different interpretation and/or activeness (9). They were originally developed to evaluate the accuracy of capillary claret glucose testing systems using a relevant departure of twenty% betwixt reference and measured values. For the report, the mistake grids were adjusted to the x% differences. The grid is subdivided into five zones: A, B, C, D, and E. Zone A represents values that differ from the reference value by <10%. Zone B represents values that differ >10% from the reference value. Results in zones A and B will lead to the aforementioned treatment decision. Zone C represents values that would event in overcorrecting adequate glucose values. Zone D represents values that are erroneously uncorrected, and zone E represents values that would effect in the changed treatment.

To detect a 10% difference between the glucose concentrations with a power of 90%, α 0.025 (1-sided equivalence examination), a total sample size of 100 participants is required. SPSS software (version xv.0) was used for all the analyses.

RESULTS

The study population consisted of 123 patients; 63 (51%) were men, and 66 (54%) were patients with type ane diabetes. Mean age was 54.4 years (SD fourteen.2), mean HbA_1c was 59 mmol/mol (SD 14) (or vii.5% SD ane.3), and hateful BMI was 29 kg/thousand² (SD 6.two). Mean hematocrit values were 0.45 L/L (SD 0.05). All values were inside the hematocrit ranges of the Accu-Chek Meaty plus meter (0.25–0.65 Fifty/L).

Control measurements

Intraclass correlations of the commencement and second drops of blood of the 3 control measurements were 0.996, 0.995, and 0.996, respectively. In ii–4% of these three command measurements, the second drib of claret differed 10% or more compared with the beginning drop of blood.

Table 1 shows median and interquartile ranges of the glucose concentration in various testing sequences in dissimilar circumstances.

Table 1

Glucose concentrations in different sequential drops of blood

	Beginning drib	Second drop	Control
Not washing hands (n = 123)	viii.9 (6.4–12.six)	eight.9 (half dozen.5–12.ii)	eight.6 (6.one–12.two)
Washing hands (n = 123)	eight.5 (vi.3–12.2)	8.seven (5.9–12.ii)	8.half dozen (6.1–12.2)
Finger exposed to fruit, no washing (north = 122)	fifteen.0 (10.5–21.7)	8.9 (6.5–12.5)	eight.ix (half dozen.four–12.2)
After washing the fruit-exposed finger (n = 121)	8.4 (6.3–11.ix)	eight.three (6.4–12.0)	8.5 (6.2–12.0)
Pressure forty mmHg (northward = 102)	8.iv (6.1–11.ix)	viii.ii (5.5–11.4)*	viii.5 (half-dozen.two–12.0)
Pressure 240 mmHg (n = 102)	8.iii (six.1–11.6)	viii.4 (5.ix–11.i)**	8.v (vi.two–12.0)

Intervention 1: not washing hands.

Not washing hands led to a ≥10% difference in glucose concentrations compared with the control measurement in the start and the second drops of blood in 11% (P < 0.001) and 4% (P < 0.001) of the participants, respectively. Two glucose concentrations in the first drop of blood were even more than xx% higher than the control measurement (Fig. iA ). Wiping away the offset drop led to 96% of the values inside the ten% differences (Fig. oneB ).

The divergence in glucose concentrations of the first (A) and second (B) drops of blood when the patient had not washed the hands vs. command measurement. (A high-quality color representation of this figure is available in the online effect.)

Intervention ii: fruit-exposed finger.

Exposing the finger to fruit led to ten% or higher glucose concentrations in the commencement drib of claret in 88% of the patients (P < 0.001) compared with the command measurements. Wiping the first drop away with a tissue considerably improved readings. In 11% of cases, however, the glucose readings from the second drib of blood were still ≥10% higher than the control measurements (P < 0.001).

Intervention 3: washing the fruit-exposed finger.

After washing their hands with soap and water, 4% (P < 0.001) and v% (P = 0.189) of the participants showed a difference of ≥10% in the glucose concentrations compared with the controls, respectively.

Figure ii shows modified Clarke error grids of fruit-exposed fingers and afterward washing fruit-exposed fingers. In the intervention with fruit-exposed fingers, 11 glucose concentrations were higher than 33.3 mmol/L. Thirty-eight percentage of the capillary glucose points of the fruit-exposed fingers were in zone C, which would issue in an overcorrection of acceptable glucose concentrations. Wiping abroad the first driblet of blood from the fruit-exposed finger led to one betoken falling in zone C and 11% in zone B. Washing the fruit-exposed fingers with soap and water led to 95% of glucose concentrations falling inside zone A.

Modified Clarke error grids of fruit-exposed fingers and after washing fruit-exposed fingers.

Intervention 4: dissimilar external pressures.

Effigy 3 shows the difference between the glucose concentrations for different pressures. The deviation between the glucose concentrations and the control measurements increased when the pressure was increased. Pressure level with twoscore mmHg led to ≥ten% differences in glucose concentrations compared with the controls in the first drop and the second drop of claret in 5% (P = 0.055) and 10% (P = 0.009) of the participants, respectively. Pressure of 240 mmHg led in 12% (P = 0.018) and 13% (P = 0.217) of the participants to ≥x% differences in glucose concentrations in the offset and second drops of blood compared with the controls, respectively.

The deviation in glucose concentrations of the start and second drops of blood vs. control measurement for different pressures. (A loftier-quality color representation of this effigy is available in the online issue.)

Blood glucose concentrations in fingers of different easily

When the measurements were performed at the same time in fingers of different done and dried hands, only ane glucose concentration (ane%) differed ≥10% (data not shown).

CONCLUSIONS

The first drop of blood can be used for self-monitored glucose testing, but only after washing hands. If washing hands is non possible and they are non visibly soiled or exposed to a sugar-containing production, it is acceptable to use the 2nd drop of claret after wiping abroad the offset driblet. It does not thing which finger is used for glucose measurements. External pressure may lead to unreliable readings.

Many insulin-treated patients have to perform SMBG for a lifetime—some of them every day. Discarding the first drop of blood and refraining from squeezing the finger makes measurements more than circuitous and necessitates deeper and more painful punctures. International guidelines and studies virtually SMBG (e.yard., the American Diabetes Clan [ADA] and the Diabetes United kingdom guidelines) recommend using the first drop of blood subsequently washing the easily (ten–12). Some also permit squeezing or milking the finger. The manufacturer's instructions of the meter used in the study include washing hands with warm water and soap and drying the hands. The first drop of blood can be used after gently squeezing the finger. In daily practice, patients cannot or do non always wash their hands before performing SMBG (one). In international guidelines, these situations are non discussed.

Merely two studies investigated the differences between glucose concentrations in the showtime and the second drops of blood. Both of these studies, however, involved volunteers without diabetes. In one study of 53 volunteers, no differences were institute in the readings when the hands were clean (13). Glucose readings for 25 volunteers in the other report were shown to be greatly affected when the fingers were exposed to glucose (i.e., fruit). Even the 3rd drib of blood cannot be used in these cases (14). Our study as well shows that the first drop of blood should not exist used when the patient has not washed the hands. Use of the second drop of blood leads to reliable values when the finger is wiped by a tissue in between obtaining the 2 drops. Nevertheless, this does non apply to fingers exposed to glucose products as the glucose concentrations in the 2d drop still differed ≥10% from the control measurements in 11% of the patients. Therefore, patients should always wash their hands when they have touched a sugar-containing product.

Fruhstorfer and Quarder (13) also investigated the influence of milking the finger in 10 volunteers without diabetes and ended that milking the finger gives correct glucose values. In our study, we used two pressures to explore whether there would be whatsoever influence on the capillary glucose concentration. Venous stasis is achieved with a pressure of forty mmHg. A pressure level of 240 mmHg is to a higher place the systolic pressure of the participants. Our study shows more than deviation between the glucose concentrations with the higher pressure.

The differences used in this study are more strict than the twenty% difference in the International Arrangement for Standardization (ISO) standard (15), or the fifteen% divergence or a difference of 1 mmol/L in cases when the glucose concentration is <6 mmol/L in the Dutch guideline (16). Patients expect meters to provide high analytical quality of blood glucose measurements (17). Furthermore, these differences may crusade errors in insulin dose when using strict insulin algorithm (eighteen). Based on the article by Jansen and Slingerland (seven), a difference of 10% cannot be neglected.

A standardized method of squeezing of the finger in daily practice is difficult because the necessity for squeezing varies strongly between individuals, depending on the construction of the skin. A limitation of our study is that the method of squeezing does not fully mimic daily practise, so the results should be interpreted with some caution. The strength of the study is that a standardized method of squeezing was used. The use of ane meter past one experienced person express variability. On the other hand, it limits generalization of the findings to other equipment. There are several aspects that could affect readings, such equally the fourth dimension of the concluding insulin dosage. Therefore, a divide control measurement was performed for each intervention. The time interval between measurements was maximal xc south, simply in most of the interventions the time interval was xxx–60 s. Using this design, it is not likely that these aspects accept relevantly influenced the results. However, we cannot completely exclude an effect of this time delay. Multivariate analyses bear witness that in none of the interventions, sex or HbA_1c had a statistically meaning influence on the results. Finally, because of the choice of the patients, the results cannot be generalized to the hospital setting.

Our written report investigated of import and underexposed aspects apropos SMBG in people with diabetes to learn a reliable glucose concentration. Based on this study, the kickoff choice is to launder the hands with soap and h2o, dry out them, and use the starting time drop of blood for SMBG. If washing easily is non possible, and they are not visibly soiled or exposed to a sugar-containing product, information technology is acceptable to utilise the 2nd driblet of blood after wiping away the kickoff drop. House squeezing of the finger should exist avoided.

Acknowledgments

The authors admit sanofi-aventis and Roche Diagnostics Nederland BV for their support.

The sponsors had no part in the study design, data collection, assay, interpretation, or writing of this article. No other potential conflicts of interest relevant to this article were reported.

J.H. researched data, contributed to discussion, and wrote the manuscript. R.J.Due south. contributed to discussion and reviewed and edited the manuscript. N.1000. contributed to give-and-take and reviewed and edited the manuscript. S.J.J.L. reviewed and edited the manuscript. K.H.One thousand. researched data and reviewed and edited the manuscript. S.T.H. contributed to discussion and reviewed and edited the manuscript. H.J.G.B. contributed to discussion and reviewed and edited the manuscript.

The authors would similar to give thanks Marion Fokkert, bespeak-of-intendance coordinator, and Wim Muller, technician, both working in the Department of Clinical Chemistry, Isala Clinics, Zwolle, holland, for their back up in the study.

References

1. Bergenstal R, Pearson J, Cembrowski GS, Bina D, Davidson J, List S. Identifying variables associated with inaccurate self-monitoring of blood glucose: proposed guidelines to improve accurateness. Diabetes Educ 2000;26:981–989 [PubMed] [Google Scholar]

ii. Dutch Diabetes Federation. Recommendations for Self-Monitoring of Claret Glucose Amersfoort, the Netherlands, 2003

iii. Dutch Association of Diabetic Care Professionals. Guidelines: Performing Self-Monitoring of Blood Glucose Utrecht, holland, 2004

iv. Dutch Diabetes Clan. Self-monitoring of blood glucose [Internet]. Amersfoort, holland. Available from http://www.dvn.nl Accessed i May 2010

6. Bland JM, Altman DG. Statistical methods for assessing understanding between two methods of clinical measurement. Lancet 1986;1:307–310 [PubMed] [Google Scholar]

7. Jansen RTB, Slingerland RJ. SKML-Quality Marking for point-of-care test (POCT) glucose meters and glucose meters for domicile-utilise. Clin Chem Lab Med 2010;48:1021–1027 [PubMed] [Google Scholar]

8. Fraser CG, Petersen PH. Desirable standards for laboratory tests if they are to fulfill medical needs. Clin Chem 1993;39:1447–1453 [PubMed]

9. Clarke WL, Cox D, Gonder-Frederick LA, Carter W, Pohl SL. Evaluating clinical accuracy of systems for self-monitoring of blood glucose. Diabetes Intendance 1987;10:622–628 [PubMed] [Google Scholar]

12. Baum JM, Monhaut NM, Parker DR, Cost CP. Improving the quality of cocky-monitoring blood glucose measurement: a report in reducing calibration errors. Diabetes Technol Ther 2006;8:347–357 [PubMed] [Google Scholar]

13. Fruhstorfer F, Quarder O. Blood glucose monitoring: milking the finger and using the first drop of blood requite correct glucose values (Letter). Diabetes Res Clin Pract 2009;85:e14–e15 [PubMed] [Google Scholar]

14. Hortensius J, Kleefstra North, Slingerland RJ, et al. The influence of a soiled finger in capillary blood glucose monitoring. Neth J Med 2010;68:330–331 [PubMed] [Google Scholar]

fifteen. International System for Standardization. ISO 15197:2003: In vitro diagnostics test systems–requirements for blood-glucose monitoring systems for self-testing in managing diabetes mellitus. [Internet], 2003. Available from www.iso.org

xvi. Mail H, van Keulen GJ, Muller WJ, Miedema M. TNO Quality Guideline PG/TG/2001.045: portable in-vitro blood monitoring systems for (self)-monitoring–blood glucose monitors–particular requirements and test methods. Netherlands System for Applied Scientific Research, Leiden, the Netherlands, November 2001 (No. 011.51275/01.02)

17. Skeie S, Thue G, Sandberg Due south. Patient-derived quality specifications for instruments used in self-monitoring of blood glucose. Clin Chem 2001;47:67–73 [PubMed] [Google Scholar]

eighteen. Boyd JC, Bruns DE. Quality specifications for glucose meters: cess by simulation modeling of errors in insulin dose. Clin Chem 2001;47:209–214 [PubMed] [Google Scholar]

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Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3041180/

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