Clinicians question the results of glycosylated hemoglobin, what's wrong?

Foreword

Foreword Foreword

Glycated hemoglobin, a form of hemoglobin, is used to reflect the average plasma glucose concentration a period of time (4 to 8 weeks) ago

Glycated hemoglobin, a form of hemoglobin, is used to reflect the average plasma glucose concentration a period of time (4-8 weeks) ago

The patient was a 67-year-old male.

Routine blood examination on December 7, 2020: RBC2.

Clinical manifestations: dizziness, fatigue, yellowish skin, brown urine, an emergency blood test in our hospital showed a significant decrease in hemoglobin, and an increase in total bilirubin and indirect bilirubin in biochemistry

On admission to the room, her vital signs were stable, her consciousness was clear, and her skin and sclera were slightly yellowish

On the second day of admission (December 8, 2020), blood test routine: RBC1.

The patient's clinical history and blood glucose and urine glucose test results suggest type 2 diabetes

The platform for testing glycosylated hemoglobin in the laboratory of our hospital is Tosoh (Tosoh Co.

Test result: the same as before

The above test indicates that the patient's glycosylated hemoglobin results for this specimen, there is no detection error

Glycosylated hemoglobin (GHb) is the product of non-enzymatic glycation between free amino groups of hemoglobin and glucose

The level of HbA1c depends on the plasma glucose level and the duration of plasma glucose elevation, is directly proportional to the plasma glucose concentration, and has nothing to do with the time of blood collection, the state of blood collection, whether or not fasting, etc.

The production process of glycosylated hemoglobin is in red blood cells, so the existence time of red blood cells will affect the level of glycosylated hemoglobin ^[1]

It is reported in the literature that the existence time of red blood cells is reduced in hemolytic anemia, which leads to a decrease in the level of glycosylated hemoglobin

The HbA1c of patients with hemolytic anemia is lower than that of non-anemic patients.

Hemolysis refers to the process of shortening the life span of red blood cells after being destroyed.
Anemia caused by hemolysis exceeding the compensatory capacity of bone marrow is called hemolytic anemia
.
According to the cause, it can be divided into hemolytic anemia caused by abnormal red blood cells and abnormal red blood cells
.

Among them, red blood cell abnormalities include hereditary and acquired red cell membrane abnormalities, hereditary red cell enzyme deficiency, hereditary globin production disorders, and heme abnormalities
.
RBC external abnormalities include immune hemolytic anemia, vascular hemolytic anemia, such as caused by other organisms, physical and chemical factors
.

Among them, red blood cell abnormalities include hereditary and acquired red cell membrane abnormalities, hereditary red cell enzyme deficiency, hereditary globin production disorders, and heme abnormalities
.
RBC external abnormalities include immune hemolytic anemia, vascular hemolytic anemia, such as caused by other organisms, physical and chemical factors
.
Immune blood vessel

The common feature of various hemolytic anemias is that the average survival time of the patient's red blood cells is shortened, which results in the shortening of the contact time between hemoglobin and HbA1c, so HbA1c is lower than normal
.
Therefore, the patient in this case has a history of diabetes, high blood sugar and high urine glucose, but the result of glycosylated hemoglobin is negative
.

The common feature of various hemolytic anemias is that the average survival time of the patient's red blood cells is shortened, which results in the shortening of the contact time between hemoglobin and HbA1c, so HbA1c is lower than normal
.
Therefore, the patient in this case has a history of diabetes, high blood sugar and high urine glucose, but the result of glycosylated hemoglobin is negative
.
Expert commentExpert comment

Reviewer: Professor Cao Yingping, Department of Laboratory Medicine, Union Hospital, Fujian Medical University

Commenting expert: Professor Cao Yingping, Department of Laboratory Medicine, Union Hospital of Fujian Medical University Commenting expert: Professor Yingping Cao, Department of Laboratory Medicine, Union Hospital of Fujian Medical University

Glycated hemoglobin is commonly used clinically to detect long-term blood sugar control in diabetic patients
.
Under normal circumstances, it can more accurately reflect the patient's blood sugar level in the past three months, which is directly proportional to the blood sugar level
.
This case started with the clinical proposal that glycosylated hemoglobin did not match the clinical diagnosis and blood glucose and urine glucose levels.
The laboratory department used nuclear substance control to repeat the test of the patient's glycosylated hemoglobin results, and consult related literature and other methods to confirm that the patient was due to hypohemoglobinemia.
The glycosylated hemoglobin test caused false negative results
.

Glycated hemoglobin is commonly used clinically to detect long-term blood sugar control in diabetic patients
.
Under normal circumstances, it can more accurately reflect the patient's blood sugar level in the past three months, which is directly proportional to the blood sugar level
.
This case started with the clinical proposal that glycosylated hemoglobin did not match the clinical diagnosis and blood glucose and urine glucose levels.
The laboratory department used nuclear substance control to repeat the test of the patient's glycosylated hemoglobin results, and consult related literature and other methods to confirm that the patient was due to hypohemoglobinemia.
The glycosylated hemoglobin test caused false negative results
.

This case analyzes several reasons that may cause the results of glycosylated hemoglobin to be inconsistent with the clinical diagnosis, and serves as a reference for the tester to interpret the results of glycosylation in the future treatment of patients with hypohemoglobinemia and hemoglobin variants
.
The whole case has clear thinking, rigorous analysis, and fluent language, which perfectly demonstrates the analysis thinking when the test results are inconsistent with the clinical diagnosis and treatment , and also serves as an example for the collaboration between the test and the clinic
.

This case analyzes several reasons that may cause the results of glycosylated hemoglobin to be inconsistent with the clinical diagnosis, and serves as a reference for the tester to interpret the results of glycosylation in the future treatment of patients with hypohemoglobinemia and hemoglobin variants
.
The whole case has clear thinking, rigorous analysis, and fluent language, which perfectly demonstrates the analysis thinking when the test results are inconsistent with the clinical diagnosis and treatment , and also serves as an example for the collaboration between the test and the clinic
.
Diagnosis and treatment

references

references

[1]Zhao Peiran.
Discuss the relationship between glycosylated hemoglobin and iron deficiency anemia [D].
Fujian Medical University, 2016.

[1]Zhao Peiran.
Discuss the relationship between glycosylated hemoglobin and iron deficiency anemia [D].
Fujian Medical University, 2016.

[2] Lu Bin, Yang Rongli.
Research progress on the effect of anemia on glycosylated hemoglobin[J].
Medical Review, 2017, 23(15): 3077-3081.

[2] Lu Bin, Yang Rongli.
Research progress on the effect of anemia on glycosylated hemoglobin[J].
Medical Review, 2017, 23(15): 3077-3081.

[3]ÇetinkayaAltuntaşSeher,EvranMehtap,GürkanEmelet al.
HbA1c level decreases in iron deficiency anemia.
[J] .
WienKlinWochenschr, 2021, 133: 102-106.

[3]ÇetinkayaAltuntaşSeher,EvranMehtap,GürkanEmelet al.
HbA1c level decreases in iron deficiency anemia.
[J] .
WienKlinWochenschr, 2021, 133: 102-106.


Leave a message here