\"note, when we talk about \'controlled\' or \'uncontrolled\' we look at the A1C
ID: 151728 • Letter: #
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"note, when we talk about 'controlled' or 'uncontrolled' we look at the A1C result, this portrays a more accurate picture to the doc about how high or low the blood glucose levels have been on average over the past 3 months For three consecutive quarters, a fasting glucose and glycosylated hemoglobin were performed on a patient. The results are as follows: QUARTER 1 QUARTER 2 QUARTER 3 Plasma 280 mg/dL 85 mg/dL 91 mg/dL glucose, fasting Glycosylated 7.8% 15.3% 8.5% 1. In which quarter was the patient's glucose best 2. Do the fasting plasma glucose and glycosylated 3. What methods are used to measure glycosylated 4. What potential conditions might cause erroneous controlled? The least controlled? hemoglobin match? Why or why not? hemoglobin? results?Explanation / Answer
1. Fasting Plasma glucose levels more than or equal to 126mg/dL indicates uncontrolled diabetes. A prediabetic person has levels greater than or equal to 100-125 mg/dL indicates a prediabetic individual.
The best quarter where the glucose levels were controlled was quarter 2 where the fasting glucose is 85 mg/dL. The least quarter where the glucose levels were controlled was quarter 1. In this quarter, fasting glucose levels were 280 mg/dL, which is more than 126 mg/dL cutoff limit.
2. Glycosylated haemoglobin is the hemoglobin that is glycosylated and is known as hemoglobin Arc or HbA. It indicates average plasma glucose levels in the preceding 8-12 weeks. This test avoids the day-to-day variability of glucose levels and it does not require the person to fast. The HbA1c levels should be more than 6.5% in uncontrolled diabetes. In prediabetes, levels range between 5.4-6.5%.
The HbA1c and the fasting plasma glucose (FGT) are not matching. This is because in even though the plasma glucose levels in quarter 2 and 3 are indicative of levels in normal individual, the HbA1c levels indicate that there is uncontrolled diabetes in both quarter. The HbA1c levels should be directly proportional to fasting glucose levels in plasma. FGT is a day to day estimation while HbA1c gives an average of the levels in 2-3 months. HbA1c can monitor both type 1 and type 2 diabetes. If the person had controlled diabetes in second and third quarter, his fasting glucose levels should have been higher than 126 mg/dL. Infact , the fasting glucose levels should have been more than 300 mg/dL in quarter 2, where the HbA1c levels were 15.8% (twice the cut off range).
3. Glycosylated hemoglobin or HbA1c is a blood test that detects the levels of glucose in blood over 2-3 months. Hemoglobin A1c is formed when there is carbonyl group of glucose and the amino group at the N-terminus of the beta chain of hemoglobin A condense. This causes formation of a labile aldimine or Schiff base. Some of the aldimine undergoes a slow, irreversible conversion to a stable ketoamine form (HbA1c) when the RBCs circulate in blood stream. Ion exchange HPLC can also be used for measurement, which combines ion exchange with HPLC. Another method is the immunoturbidimetric inhibition assay. Here, a polyhapten reagent containing multiple HbA1c epitopes will compete with the HbA1c in patient sample for anti-HbA1c antibody binding sites.
HbA1c levels are estimated by high performance liquid chromatography or HPLC. Blood samples were collected by standard phlebotomy into EDTA tubes post fasting. HPLC is performed and the HbA1c result is calculated as a ratio glycosylated Hemoglobin to total hemoglobin. In HPLC, the sample present in a solvent (mobile phase) is pumped at high pressure over a column packed with chromatographic materials (stationery phase). A gas stream of helium or nitrogen carries the sample over the column. Separation depends on the relative affinity of the sample for mobile phase and stationery phase.
4. Pregnancy, renal failure or haemoglobinopathies may give a false positive HbA1C test. Genetic variants such as HbS, HbC traits, elevated fetal hemoglobin (HbF) and presence of carbamylated hemoglobin in renal failure patients can elevate HbA1c levels. Low HbA1c levels will be seen in diabetic patients when there exists a condition in patients that reduces erythrocyte survival. High HbA1c levels are seen in patients with iron deficiency anemia.
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