• Korean Journal of Clinical Laboratory Science
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• v.41 no.1
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• pp.37-41
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• 2009

Measurement of hemoglobin A1c is used as an objective indicator of long-term blood glucose control in diabetic patients. We evaluated recently introduced Norudia$^{(R)}$ HbA1c (Daiichi Pure Chemical Co. Ltd, Tokyo, Japan) test reagent using enzyme method for HbA1c assay. Linearity, precision and correlation with VARIANT$^{TM}$ II Turbo HbA1c analyzer (BIO-RAD, Hercules, CA, USA) were evaluated. The reference range was determined from 201 healthy subjects. The Norudia$^{(R)}$ HbA1c test reagent was founded to be linear in a range of 5.6% to 14.0% ($r^2=0.9885$). The within-run and between-day precision were 0.954% and 1.03% for low level (HbA1c 5.24%), 0.67% and 1.28% for high level (HbA1c 9.01%), respectively. Comparison study between Norudia$^{(R)}$ HbA1c test reagent and VARIANT$^{TM}$ II Turbo showed good correlation with a slope of 1.0489. an intercept at -0.9717, and coefficient of correlation was 0.9907. The reference range of HbA1c obtained from this reagent was 4.07-5.50%. The Norudia$^{(R)}$ HbA1c test reagent showed good linearity, precision and correlation with HbA1c analyzer with HPLC method. In addition, the exclusive analyzer is not required for assay and then this kit may be useful for HbA1c assay in clinical laboratory.

• Journal of Periodontal and Implant Science
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• v.51 no.2
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• pp.114-123
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• 2021

Purpose: This retrospective cohort study aimed to assess the effect of nonsurgical periodontal therapy on glycated hemoglobin (HbA1c) levels in patients with both type 2 diabetes and chronic periodontitis. Methods: The intervention cohort (IC) comprised 133 patients with type 2 diabetes who received nonsurgical periodontal treatment, while the matching cohort (MC) included 4787 patients with type 2 diabetes who visited the Department of Endocrinology and Metabolism of Asan Medical Center. The patients in each cohort were divided into 3 groups according to their baseline HbA1c level: subgroup 1, HbA1c <7%; subgroup 2, 7%≤ HbA1c <9%; and subgroup 3, HbA1c ≥9%. Changes in HbA1c levels from baseline to 6 and 12 months were analyzed. In addition, the association between changes in HbA1c levels and the number of periodontal maintenance visits was investigated. Results: There were no statistically significant changes in HbA1c levels in the IC and MC or their subgroups when evaluated with repeated-measures analysis of variance. However, the IC showed maintenance of baseline HbA1c levels, while the MC had a trend for HbA1c levels to steadily increase as shown by pairwise comparisons (baseline to 6 months and baseline to 12 months). IC subgroup 1 also maintained steady HbA1c levels from 6 months to 12 months, whereas MC subgroup 1 presented a steady increase during the same period. The number of periodontal maintenance visits had no association with changes in HbA1c levels during the 1-year study duration. Conclusions: For patients with both type 2 diabetes and periodontitis, nonsurgical periodontal treatment and periodontal maintenance may help to control HbA1c levels.

• Korean Journal of Clinical Laboratory Science
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• v.42 no.3
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• pp.125-128
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• 2010

HbA1c test measures the amount of glycated hemoglobin in blood. HbA1c shows the average of blood glucose levels for the past three months, this is a better indicator of how overall diabetes is doing. HbA1c gives a much better idea of how the body is breaking down the glucose. Therefore, this HbA1c is very important tool for maintaining normal glucose levels for pre-and diabetic patients. Total 408 participants were tested HbA1c voluntarily from Chosunilbo Health Expo (8th~11th, July 2010). Through this small-scaled direct HbA1c, about 54.7% (207 out of 408) was shown glucose tolerance and diabetes. However, 61 from 157 participants who were shown under 6.9% HbA1c (normal and pre-diabetic stage) are taking only antidiabetic drugs to maintain a normal blood glucose. Regular HbA1c test can bring an important management and awareness about controlling blood sugar level and prevention of diabetic complications.

• Laboratory Medicine Online
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• v.2 no.1
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• pp.10-14
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• 2012

Background: Measurement of HbA_1c levels is widely used to diagnose diabetes mellitus and to evaluate and monitor plasma-glucose concentrations over 6-8 weeks. In this study, we evaluated the diagnostic performance of the newly developed latex immunoturbidimetric method by using Autolab HbA_1c. Methods: We analyzed and compared the diagnostic performance of Autolab HbA_1c with that of Toshiba 200FR between April 2009 and July 2009. According to guidelines (EP5-A2, EP6-P, EP9-A2) of the clinical and laboratory standards institute (CLSI), we compared linearity, precision and correlation of Autolab HbA_1c with those of G7 (Tosoh Corp., Kyoto, Japan) by using high-performance liquid chromatography (HPLC) method. Results: Data obtained using Autolab HbA_1c showed good linearity in mixtures of samples with low (3.1%) and high (15.1%) levels of HbA_1c (r²=0.9997). In the analysis of within-run precision of the samples with HbA_1c levels of 5.1% and 12.1%, the SDs were 0.04 and 0.06 and covariances of these samples were 0.8% and 0.5%, respectively. In the Deming regression model, the regression equation was as follows: Autolab HbA_1c=1.0859×Tosoh HPLC-0.6957. Conclusions: In this study, Autolab HbA_1c method showed better performance characteristics than Tosoh G7 did. In reference review, there was no interference of variant hemoglobin. The data acquisition time of Autolab HbA_1c was lower than that of Tosoh G7. The advantages of Autolab HbA_1c are that it can be used as an autoanlyzer in routine chemical analysis, it does not require pre-analytical treatment, and the samples are automatically treated with distilled water for hemolysis.

• Korean Journal of Clinical Laboratory Science
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• v.43 no.4
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• pp.171-178
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• 2011

Glycated hemoglobin ($HbA_{1c}$) is a most preferably used baseline of diabetes, implicating average blood glucose levels over a 2-3 month period of time. Recently the American Diabetes Association has recommended the $HbA_{1c}$ assay as one of the criteria for diabetes. Although some studies provide data with "estimated average glucose", by converting the $HbA_{1c}$ results from simple linear regression, the results are not applicable to whole diabetes. We compared the relationship between $HbA_{1c}$ and estimated average glucose by anemia degree of diabetic patients in Korea. The data from the 2008~2009 Korean National Health and Nutrition Examination Survey were used. Analysis was done for 1,257 diabetes subjects with $HbA_{1c}$ results. The distribution of subjects was 34.1% in 60's, 25.9% in 70's, 21,6% in 50's, showing that there was more than 80% in over 50's. To take a close look of the differences depending on the anemic degree, we applied WHO criteria (hemoglobin<13.0 in men and hemoglobin<12.0 in women) and divided anemia degree. The regression equation for A1c and estimated average glucose was $eAG_{mg/dL}=24.3{\times}A1c-32.0$ ($R^2=0.54$, p<0.001) in all subjects, $eAG_{mg/dL}=33.1{\times}A1c-96.1$ ($R^2=0.52$, p<0.001) in slight anemia ($11.0{\leq}$Hb<13.0 in men, $10.0{\leq}$Hb<12.0 in women), and $eAG_{mg/dL}=13.5{\times}A1c+34.9$ ($R^2=0.12$, p =0.075) in moderate anemia (Hb<11.0 in men, Hb<10.0 in women). The regression was not significant in moderate anemia. The relationship between HbA1c and eAG was lower correlation than ADAG study, and eAG showed lower value in all ranges among $HbA_{1c}$ 5~13%. Such as a korea where, there are many diabetic patients among the old aged and higher prevalence rate of anemia, we should be extra careful when we reflect eAG using $HbA_{1c}$ and need to establish criteria which can be applicable to koreans.

• Journal of Sensor Science and Technology
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• v.28 no.5
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• pp.305-310
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• 2019

The purpose of this study is to classify the concentration of HbA1c (glycosylated hemoglobin), which is an indicator in the management of accurate blood glucose level in diabetic patients, using a non-invasive optical property measurement method. To measure the optical properties of HbA1c, the optical source uses LEDs and laser diodes of 400 nm in the visible region and 1450 nm in the nearinfrared region using thermopile to detect the Raman scattering intensity. An HbA1c control solution was used. As a result, the optical properties of 5% (normal) and 9% (abnormal) HbA1c control solutions showed specificity in which the output values were reversed at 850 nm and 950 nm, respectively. This property was applied to distinguish between normal and abnormal values in diabetes. In addition, considering tissue penetration depths for non-invasive measurements, two wavelengths were determined to be effective in distinguishing the concentrations of HbA1c control solutions at 5%, 7%, and 9%.

• Mass Spectrometry Letters
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• v.5 no.2
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• pp.52-56
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• 2014

Glycated hemoglobin (HbA1c) is used as an index of mean glycemia over prolonged periods. This study describes an optimization of enzyme digestion conditions for quantification of non-glycated hemoglobin (HbA0) and HbA1c as diagnostic markers of diabetes mellitus. Both HbA0 and HbA1c were quantitatively determined followed by enzyme digestion using isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) with synthesized N-terminal hexapeptides as standards and synthesized isotope labeled hexapeptides as internal standards. Prior to quantification, each peptide was additionally quantified by amino acid composition analysis using ID-LC-MS/MS via acid hydrolysis. Each parameter was considered strictly as a means to improve digestion efficiency and repeatability. Digestion of hemoglobin was optimized when using 100 mM ammonium acetate (pH 4.2) and a Glu-C-to-HbA1c ratio of 1:50 at $37^{\circ}C$ for 20 h. Quantification was satisfactorily reproducible with a 2.6% relative standard deviation. These conditions were recommended for a primary reference method of HbA1c quantification and for the certification of HbA1c reference material.

• KSBB Journal
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• v.14 no.4
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• pp.422-428
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• 1999

A transformat Alcaligence eutrophus GA5 harboring phbC gene from A. latus was cultivated for production of Poly(3-hydroxybutyrate-4-hydroxybutyrate)[P(3HB-4HB)] containing high molar fraction of 4-hydroxybutyrate(4HB)] containing high molar fraction of 4-hydroxybutyrate(4HB). Transformation did not influenced significantly on total cell growth, on total cell growth, concentration, and content of P(3HB-4HB), however, significantly influenced on 4HB molar fraction in P(3HB-4HB) increasing from 12.3 to 23.5 mol% after 48 h cultivation in two-stage using 1.0%(W/V) of ${\gamma}$-butyrolactone as a precursor compare to parent strain. Above increment may be due to the accelerated polymerization between 3HB and 4HB converted from precusor compound by amplified phbC gene. Citrate increased remarkbly total cell mass and P(3HB-4HB) concentration, but did not influenced on the molar fraction of 4HB, meanwhile, magnesium ion influenced on P(3HB-4HB) concentration and 4HB molar fraction significantly. The two-stage cultivation method was modified, in such a way minimizing P(3HB) accumulated inside of cell grown at first-stage, consquently, 26.3% of P(3HB-4HB) containing 61.0 mol% of 4HB fraction was obtained after 72hr. Furthermore, semi-homopolymeric P(4HB) containing 92.0 mol% of 4Hb was obtained, and its structure was confirmed by $^1$H-NMR.

• Journal of the Korean Dietetic Association
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• v.19 no.2
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• pp.112-123
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• 2013

HbA1c was recently adopted as a reliable indicator for screening diabetes. This study investigated the ability of nutrition consultation to prevent diabetes in overweight women (BMI 23 $kg/m^2$ or more) using HbA1c as an indicator. Twenty overweight and obese women (with $HbA1c{\geq}5.7$%) completed the 12-week nutritional study, with individual and personalized nutrition counseling performed every 2 weeks. The main study guidelines involved the following: 1) reducing the intake of high fat foods and alcohol, 2) consuming a large amount of vegetables, 3) reducing the intake of simple sugars and empty-calorie foods, and 4) increasing physical activity to ${\geq}30$ min/day. Anthropometric (height, weight, BMI, body muscle (kg), body fat (%), waist and hip circumference, blood pressure) and biochemical parameters (fasting blood sugar (FBS), HbA1c, lipid profiles, hs-CRP) were measured before and after the nutrition consultation. After 12 weeks, the HbA1c<5.7% group had significant decreases in BMI, WC, HC, WHR, HbA1c, hs-CRP and also dietary intake of energy (P<0.01), carbohydrates, lipids (P<0.01), proteins (P<0.01) and cholesterol was significantly decreased (P<0.05). In the HbA1c ${\geq}5.7$% group, HbA1c, TC, LDL, NON-HDL, hs-CRP and dietary intake of energy, carbohydrate, lipid, protein, and cholesterol significantly decreased (P<0.05). These results suggest that nutrition consultation effectively helps to prevent diabetes in overweight and obese women after applying HbA1c standards. Overall, the improvement in all markers measured suggest that HbA1c is a good indicator for blood glucose regulation, helping to prevent diabetes.

• Korean Journal of Clinical Laboratory Science
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• v.41 no.2
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• pp.62-66
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• 2009

HbA1c is the major fraction of glycated hemoglobin, and used primarily to identify the average plasma glucose concentration over prolonged periods of time, mostly 2-3 months. It is used as markers for the diagnosis and monitoring of diabetic patients and increasingly used a marker in health screening check up for general populations. In this study, HbA1c was measured with Cobas integra 800 (Roche Diagnostics, Mannheim, Germany), using immunoturbidimetry principles. We established the reference interval for HbA1c with Cobas integra 800 and evaluated its significance. The study subjects were 36,140 (male 57.5%, and female 42.2%) who visited the Health Promotion Center of a tertiary care center in Seoul for health checkup from January to September, 2008. HbA1c levels were measured with immunoturbidimetric method. Statistical evaluation was done with SPSS. Comparison between male and female was checked with Mann-Whitney test, and among age groups with Kruskal-Wallis test. Reference interval for HbA1c was from 4.8% to 6.1%. There was no significant difference between male and female with Mann-Whitney test (P=0.539). There was significant difference among age groups with Kruskal-Wallis test (P<0.05). Reference interval for HbA1c with Cobas integra 800 was 4.8~6.1%, which was different from conventional one, 4.4-6.4%. Establishment of reference interval for each principle is needed.