Association of hemoglobin H (HbH) disease with hemoglobin A1c and glycated albumin in diabetic and non-diabetic patients

Aptamer-Protein Interactions: From Regulation to Biomolecular Detection

Serving as the basis of cell life, interactions between nucleic acids and proteins play essential roles in fundamental cellular processes. Aptamers are unique single-stranded oligonucleotides generated by in vitro evolution methods, possessing the ability to interact with proteins specifically. Altering the structure of aptamers will largely modulate their interactions with proteins and further affect related cellular behaviors. Recently, with the in-depth research of aptamer-protein interactions, the analytical assays based on their interactions have been widely developed and become a powerful tool for biomolecular detection. There are some insightful reviews on aptamers applied in protein detection, while few systematic discussions are from the perspective of regulating aptamer-protein interactions. Herein, we comprehensively introduce the methods for regulating aptamer-protein interactions and elaborate on the detection techniques for analyzing aptamer-protein interactions. Additionally, this review provides a broad summary of analytical assays based on the regulation of aptamer-protein interactions for detecting biomolecules. Finally, we present our perspectives regarding the opportunities and challenges of analytical assays for biological analysis, aiming to provide guidance for disease mechanism research and drug discovery.

Undetectable high-performance liquid chromatography haemoglobin A1c on variant haemoglobin E phenotype: a case report

The gold standard for long-term monitoring of diabetic patients is glycated haemoglobin (HbA1c), which is routinely tested for glycaemic control. Furthermore, the National glycohemoglobin standardization program (NGSP) has designated high-performance liquid chromatography (HPLC) as the reference method for HbA1c measurement. A woman from the Sumba tribe, Indonesia, aged 52, visited the Internal Medicine Clinic for a routine check-up. She had been taking diabetic and hypertension medicines on a regular basis for over 10 years. The HPLC procedure yielded "no result" for the patient's HbA1c assessment and there was no peak on the HPLC graphic. However, there was a discrepancy between the data history of HbA1c measured by turbidimetric method (average of 51 mmol/mol, reference range < 48 mmol/mol), fasting blood glucose (average of 7.7 mmol/L, reference range < 7.0 mmol/L) and 2-hour plasma glucose (average of 13 mmol/L, reference range < 11.1 mmol/L). Glycated albumin was 3.1 mmol/L (reference range 1.8-2.4 mmol/L). Haemoglobin electrophoresis identified homozygote haemoglobinopathy E (HbE). Patients with haemoglobin variants are proposed to utilize glycated albumin.

HbA1c and biomarkers of diabetes mellitus in Clinical Chemistry and Laboratory Medicine: ten years after

Since its discovery in the late 1960s, HbA_1c has proven to be a major biomarker of diabetes mellitus survey and diagnosis. Other biomarkers have also been described using classical laboratory methods or more innovative, non-invasive ones. All biomarkers of diabetes, including the historical glucose assay, have well-controlled strengths and limitations, determining their indications in clinical use. They all request high quality preanalytical and analytical methodologies, necessitating a strict evaluation of their performances by external quality control assessment trials. Specific requirements are needed for point-of-care testing technologies. This general overview, which describes how old and new tools of diabetes mellitus biological survey have evolved over the last decade, has been built through the prism of papers published in Clinical Chemistry and Laboratory Medicine during this period.

Identification of Hemoglobin Variants Prevalent in China and Their Effects on Hemoglobin A1c Measurements

OBJECTIVES

We aimed to evaluate the effects of hemoglobin (Hb) variants prevalent in China on HbA1c measurements and to identify them during HbA1c measurements.

METHODS

We evaluated a cation-exchange high-performance liquid chromatography (HPLC) method (Bio-Rad D-100), a capillary electrophoresis (CE) method (Capillarys 3 TERA), an immunoassay (Cobas c501), and a boronate affinity method (Premier Hb9210, as a comparative method) for HbA1c measurements in the presence of Hb variants prevalent in China.

RESULTS

The Bio-Rad D-100 and Capillarys 3 TERA gave specific retention times and numeric migration positions for each Hb variant, respectively, showing excellent interindividual reproducibility. All methods showed statistically significant differences (P < .01) for several variants. Clinically significant effects were observed for the Bio-Rad D-100 (Hb New York and Hb J-Bangkok), Capillarys 3 TERA (Hb New York and Hb J-Bangkok), and Cobas c501 (Hb New York). Among 297 samples with Hb variants, there were 75 (25.3%) unacceptable results for Bio-Rad D-100, 28 (9.4%) for Capillarys 3 TERA, and 19 (6.4%) for Cobas c501 compared with the results from Premier Hb9210.

CONCLUSIONS

Some Hb variants prevalent in China affect HbA1c measurements. The HPLC retention time and CE migration position can aid in the presumptive identification of Hb variants.

Discordantly high HbA1c may assist in diagnosing α-thalassemia but not diabetes: A case report

Glycated hemoglobin (HbA1c) is an important method for monitoring blood glucose and diagnosing diabetes. High‐performance liquid chromatography is more commonly used in the laboratory for the detection of HbA1c. Although HbA1c detected by high‐performance liquid chromatography is susceptible to abnormal hemoglobin, there are few reports that it is affected by α‐thalassemia. Previous reports have generally concluded that α‐thalassemia does not affect or lower HbA1c. Here, we report a case of discordantly high HbA1c inconsistent with fasting blood glucose. Finally, the patient was diagnosed with α‐thalassemia and insulin resistance. α‐Thalassemia might lead to a discordantly high HbA1c result, which could be attributed to elevated hemoglobin H. In this case, glycated albumin might accurately reflect the real average level of blood glucose. When finding discordant HbA1c, patients should be advised to undergo thalassemia and hemoglobinopathy screening by diabetologists/endocrinologists or primary care physicians to avoid a missed diagnosis of hematopathy.

Case Report: Abnormally Low Glycosylated Hemoglobin A1c Caused by Clinically Silent Rare β-Thalassemia in a Tujia Chinese Woman

BACKGROUND

Glycosylated hemoglobin A1c (HbA1c) is an important means of monitoring blood glucose and diagnosing diabetes. High-performance liquid chromatography (HPLC) is the most widely used method to detect HbA1c in clinical practice. However, the results of HbA1c by HPLC are susceptible to hemoglobinopathy. Here, we report a case of discordantly low HbA1c with an abnormal chromatogram caused by rare β-thalassemia.

CASE DESCRIPTION

A 36-year-old Tujia Chinese woman presented with an abnormally low HbA1c level of 3.4% by HPLC in a health check-up. The chromatogram of HbA1c showed an abnormal peak. Fasting blood glucose, routine blood tests and serum bilirubin were normal. Her body mass index was 27.86 kg/m². Hemoglobin electrophoresis showed low hemoglobin A and abnormal hemoglobin β-chain variants. The thalassemia gene test suggested a rare type of β-thalassemia (gene sequencing HBB: c.170G>A, Hb J-Bangkok (GGC->GAC at codon 56) in a beta heterozygous mutation). Glycated albumin (GA) was slightly increased. Oral glucose tolerance tests (OGTT) and insulin release tests indicated impaired glucose tolerance and insulin resistance. The hematologist advised follow-up visits. The endocrinologist recommended that the patient adopt lifestyle intervention. Three months later, GA returned to normal, and impaired glucose tolerance and insulin resistance improved.

CONCLUSIONS

Clinically silent β-thalassemia may lead to low HbA1c values and abnormal chromatograms by HPLC. In these circumstances, differential diagnosis is important. Checking the chromatogram may be helpful in interpreting HbA1c as well as identifying hemoglobinopathy. Further tests, such as GA, OGTT, hemoglobin electrophoresis and genetic tests, are needed for differential diagnosis.