BG testing

Question 1

oral glucose tolerance tests are mainly used for diagnosis of …. and may be required when….

Answer 1

impaired glucose tolerance
may be required when less severe symptoms and BG conc does not establish or exclude diabetes e.g impaired fasting glycaemia

Question 2

OGTT are also used to establish the presence of…

Answer 2

gestational diabetes

Question 3

what does an OGTT involve

Answer 3

• measuring BG conc after fasting, then 2 hours after drinking a standard anhydrous glucose drink

Question 4

glycated haemoglobin forms when…

Answer 4

RBC are exposed to glucose in plasma

Question 5

HbA1c test reflects the average plasma glucose over the previous …….. months and provides good indicator of glycemic control

Answer 5

2-3 months

Question 6

advantages of HbA1c over OGTT

Answer 6

• provides good indication of glycaemia control
• can be performed at any time of day and does not require special prep like fasting

Question 7

HbA1c is used to monitor glycaemic control in both T1D and T2D, but is only used as for diagnosis for…

Answer 7

T2D

Question 8

do not use HbA1c as diagnosis for

Answer 8

• suspected T1D
• children
• pregnancy
• women up to 2 months PP
• symptoms of diabetes for <2 months
• high diabetes risk and acutely ill
• treatment with meds that may cause hyperglycaemia (e.g. diuretics)
• acute pancreatic damage
• end stage CKD
• HIV

Question 9

HBA1c used for diagnosis should being interpreted with caution in pt with…

Answer 9

• abnormal HB
• anaemia
• altered red cell lifespan
• recent blood transfusion

Question 10

how often should HbA1c be measured in pt with T1D

Answer 10

• every 3-6 months
• more freq if BG control is thought to be changing rapidly

Question 11

how often should HbA1c be measured in pt with T2D

Answer 11

monitored every 3-6 months until HbA1c and medication are stable when monitoring can be reduced to every 6 months

Question 12

HbA1c monitoring is invalid for pt with disturbed erythrocyte turnover or for pt with a lack of, or abnormal Hb . what can you use instead

Answer 12

quality-controlled plasma glucose profiles
total glycated Hb estimation (if there is abnormal hb)
fructosamine estimation

Question 13

Lab measurement of fructosamine concentration measures….

Answer 13

the glycates fraction of all plasma proteins over the previous 14-21 days but is a less accurate measure of glycaemic control than HbA1c