Higher levels of glycosylated hemoglobin (HbA1c) indicate diabetes, as elevated HbA1c reflects chronic high blood glucose over 2-3 months.​

Option Analysis

High hemoglobin level (A): High hemoglobin typically does not directly cause elevated HbA1c; instead, HbA1c measures glucose attachment to hemoglobin regardless of total levels, though conditions like polycythemia may slightly influence readings indirectly.​

Anaemic condition (B): Anemia often lowers HbA1c due to shorter red blood cell lifespan in hemolytic types or falsely elevates it in iron deficiency via prolonged RBC exposure to glucose, but higher HbA1c specifically signals poor glucose control, not anemia itself.​

Diabetes (C): Correct answer. HbA1c ≥6.5% diagnoses diabetes by showing average hyperglycemia, as glucose binds irreversibly to hemoglobin in red blood cells over their 90-120 day lifespan.​

Favism (D): Favism, a hemolytic anemia from G6PD deficiency triggered by fava beans, shortens RBC lifespan and lowers HbA1c, not raises it, due to reduced glucose exposure time.​

Higher levels of glycosylated hemoglobin (HbA1c) indicate diabetes, serving as a key biomarker for average blood glucose over 2-3 months. This non-enzymatic glycation process attaches glucose to hemoglobin in red blood cells, with levels ≥6.5% confirming diabetes diagnosis per WHO/ADA guidelines. For CSIR NET aspirants, understanding HbA1c’s role in endocrinology and clinical biochemistry is crucial.​

HbA1c Test Mechanism

Hemoglobin A1c forms when blood glucose binds to the N-terminal valine of hemoglobin’s beta chain, reflecting glycemia since RBCs live ~120 days. Higher levels signal sustained hyperglycemia, aiding diabetes monitoring beyond fasting glucose.​​

• Normal: <5.7%

• Prediabetes: 5.7-6.4%

• Diabetes: ≥6.5%​

Why Not Other Options?

Iron deficiency anemia may falsely elevate HbA1c via extended RBC lifespan, but treatment normalizes it without indicating diabetes. Favism causes acute hemolysis, dropping HbA1c due to young RBCs with less glycation. High hemoglobin (e.g., polycythemia) shows no direct HbA1c rise.​

Clinical Relevance for Exams

In competitive exams like CSIR NET, recognize HbA1c’s specificity for diabetes over hemolytic disorders. Factors like hemoglobinopathies alter readings, requiring confirmatory tests. Target <7% for diabetic management to prevent complications.​