This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Diabetes Mellitus, Subject name: Medicine
Which of the following is true about glycosylated haemoglobin? 
Select and explain. 
A. Increased in diabetic patients with sickle cell anaemia, B. It is a poor indicator of long term diabetic status in patient with renal disease, C. Contain Haemoglobin with sugar moiety, D. Half- life is 45 days in adults
C: Contain Haemoglobin with sugar moiety
Answer: C: Contain Haemoglobin with sugar moiety 
Explanation: Glycosylated haemoglobin is not a reliable test in patients with hemoglobinopathies like thalassemia and sickle cell anemia. It is an excellent test indicating poor glycemic control in diabetics and higher valuesare associated with microvascular complications. It is a retrospective test indicating glycemic control for 8-12 weeks.