The Evaluation of Hba1c Test as A Diagnostic Test for Diabetes Mellitus Type 2

The HbA1c test and the blood glucose test were compared in order to diagnose type 2 diabetes and determine the best cut-off point for the HbA1c test for optimal sensitivity in the population of Mosul city (inside it and some rural areas around it). The test was performed on a group of people between the ages of 40 and 85 who came to our laboratory after being diagnosed with or without type 2 diabetes by specialists in internal medicine and endocrinology. The HbA1c and FBS analysis were carried out between January 2020 and January 2021. And, by using ROC curve, the results for 80 individuals with an average age of 56 years produced a HbA1c test with a value of 6.8 percent, a sensitivity of 94 percent, compared to the result of 126 mg/ml for FBS as a diagnostic criterion , and the optimal cutoff point for HbA1c was reached for 6.86% in diagnosing disease diabetes type 2 was given the highest Yuden index by ROC curve analysis. Conclusion: We recommend that the optimal value of Hb with a percentage of 6.86 percent be used as the best test in diagnosing type 2 diabetes and obtaining the best medical and health care for the Mosul population. Keyword: HbA1c, Diabetes, Type 2 مييقت صحف ركسلا يمكارتلا HbA1C رابتخاك صيخشت ي ىضرمل يركسلا يناثلا عونلا نم


Introduction
Diabetes is a chronic metabolic disease characterized by high blood sugar levels, and it causes significant damage to the nerves, blood vessels, kidneys, and eyes over time (IDF2013). 1 Diabetes type 2 has become the most common and prevalent in the last four decades. The incidence of this disease has increased in all countries and at all levels. More than 422 million people in the world suffer from diabetes type 2. Also, 1.6 million deaths every year are attributed to this disease (Brooks et al). 2 And there is a global agreement to prevent this disease and eliminate obesity by 2025. 1 Diabetes type 2 is characterized by a long clinical phase, so early and accurate diagnosis is critical (Singer et al). 3 The World Health Organization recommends using a 6.5 percent glycated hemoglobin HbA1c test as the diagnostic cut-off limit for this disease. HbA1c is primarily defined as an atypical hemoglobin for diabetics over the age of forty years. 4,5 Glycoproteins are formed after conversion through a slow, nonenzymatic interaction between blood sugar (glucose) and amino groups on proteins, which is an important and clinically useful indicator. For average blood sugar during the previous 120 days ( which is the average age of red blood cells). 6 and the introduction of the HbA1c test as a diagnostic tool for diabetes and the cut-off point is the focus of controversy and study for many years, and many studies have been conducted in this field and for residents from different countries to reach the limit. 7 Diagnostic interval. Carefully controlled studies have documented a close relationship between HbA1c concentration and glycemic control. And in this regard, the people of Mosul should be provided with a high level of care in order to avoid spreading the disease. As a result, this study was carried out to determine the cut-off value and diagnostic tool for HbA1c levels in the Mosul population.

Materials And Methods
The study was conducted in a specialized pathology analysis laboratory licensed by the Iraqi Ministry of Health on 80 residents of Mosul from January 2020 to January 2021, all of whom were over 40 years old. As 17 of them were diagnosed as having diabetes type 2 by certified specialists who were newly diagnosed with monitoring their blood pressure measurement. Diabetes is diagnosed by measuring blood glucose levels after fasting for 8 to 12 hours and finding that the level is greater than 126 mg/dl. Their infection was known from taking the treatment. Those with a history of blood transfusions within three months, those taking aspirin, and those with chronic liver and kidney disease were excluded. The family history of diabetes was studied for each individual along with age, height, weight, blood pressure, waist circumference and hip circumference. Boditech's I CHROMA TM II +® kit was used to measure HbA1c levels. HbA1c and total hemoglobin are measured using integrated advanced immunoassay and dry chemistry technology, respectively.The capillary blood sample was used with appropriate precautions. Calibrated according to the blood sample set and other standard materials supplied to us by the manufacturer.

Statistics
The analysis was carried out using the statistical software program Minitab version 17 with the assistance of statistical experts. The SPSS program version 23 was used to create the sensitivity curve and the rock curve, and all of these programs are available on my personal computer.

Ethics
The consent of all study subjects was obtained. Note that it is an analytical and statistical study and it did not harm any individual material, health or moral .

Thanks and Appreciation
I extend my thanks and gratitude to Al-Kawthar Laboratory for Pathological Analysis (a private laboratory licensed by the Iraqi Ministry of Health) for helping me complete the practical aspect of the research.

Results
The diabetes type 2 group consisted of 9 females and 8 males, while the non-diabetic group consisted of 36 females and 27 males among the 63 people. Table No. 1 shows the characteristics of the study participants. With the determination of HbA1c values, the blood glucose test (FBS) was adopted as a diagnostic criterion for type 2 diabetes with the estimation of HbA1c levels (Table No. 2) To determine the relationship between FBS and HbA1c (Fig. 1), a linear regression analysis was performed, and the stability of the highest and most credible analysis degree was demonstrated (Table No. 3, 4 and 5) and the equation produced the relationship between the two tests was produced by the equation: HbA1c (%) = 2.021 + 0.03932 x FBS (mg/dl) And for the value of 126 mg/dl for the FBS test, it is 6.97%, and for the value for 6.5% for the Hb1Ac test, the value is 113.911 mg/dl.      A rocker curve was created to determine the optimal cut for the resulting values (Fig. 2) (Table No. 6). The value 6.5 % for HbA1c assay showed a sensitivity of 100% and the optimum cutoff value for HbA1c assay was 6.86%, which recorded a sensitivity of 94%, which gave the maximum Youden Index. With a value of 84% (Table No. 7 & histogram).

Discussion
It is known that the HbA1c test has a lower sensitivity in Europeans compared to Asians, as was indicated by Mustafa et al 8 . In this study, we demonstrated the high sensitivity of the HbA1c test for Mosul residents, and the value of 6.5 % is a sensitivity of 100 %, which is an extremely high value. Also, the linear relationship between FBS test and HbA1c test is HbA1c = 1.51 + 0.0414 x FPG as explained by Liang et al 9 , which gives the value 6.72% for the test of HbA1c compared with the value of 126 mg/dl for the test. It gives a value of 120.5 mg/dl for 6.5% of the HbA1c test. And our linear analysis showed that the most accurate and the most sensitive relationship is HbA1c (%) = 2.021 + 0.03932 × FBS (mg/dl), so the ratio of FBS = 126 mg/dl is equal to 6.97% of HbA1c and for the value of 6.5% of HbA1c is equivalent to 113.911 mg In his study, Ogawa et al 10 19 The following values are 5.5,5.8, 5.9,5.9, 5.95, 6.1, 6.15, 6.3 and 6.45, which are all below the limit set by the World Health Organization, respectively. There are also studies that have put values higher than those set by the World Health Organization as in Jung et al 20 (6.75%) and Higgins et al 21 (7%). A 6year study conducted by (NHANES) Buell et al 22 (National Health and Nutrition Examination Survey) suggested 7% as the cut-off value for diagnosis. The Association of British Diabetes Doctors 23,24 (ABCD) provided a higher level of 7.2% to reduce the incidence of diabetes type 2. The US Department of Defense's Veterans Affairs also introduced a 7% cut-off point for the HbA1c test. 25,26 In this study, we excluded many factors that impair access to the ideal focal point, such as kidney failure, anemia, blood transfusion, and taking medications that affect the study. Conducting such studies on the population of the city of Mosul is considered to be of great benefit in diagnosing or controlling diseases, especially chronic diseases.

Conclusions
A cut-off value of 6.86% is considered the diagnostic criterion for diabetes type 2 as it gave the optimum sensitivity to the HbA1c test. The relationship between HbA1c and FBS is: HbA1c (%) = 2.021 + 0.03932 x FBS (mg/dl)