Selection of clinical laboratory tests in detecting and tracking disturbance of carbohydrate metabolism in patients with diabetes mellitus - basic, extended and specialized laboratory tests (glycated proteins, microalbuminuria) and their discussion.
Fructosamine is a compound that can be considered the result of non-enzymatic reaction between glucose and amine from serum proteins such as albumin and are known also as glycated serum protein. Glycated protein determines the average glucose over the past 2-3 weeks.
indications for investigation: useful in situations where the HbA1c cannot be reliably measured. Instances where fructosamine may be a better monitoring choice than A1C include:
- i. Rapid changes in diabetes treatment
- ii. Diabetic pregnancy
- iii. RBC loss or abnormalities
Specimen: serum Reference ranges: 285 μmol/l, mean 240 μmol/l. Compensated diabetes up to 350 μmol/l, decompensated over 350 μmol/l.
Result interpretation: Normal fructosamine levels may indicate that a patient is either not diabetic (and therefore should not be monitored) or that he has good diabetic control. A trend from high to normal fructosamine levels may indicate that changes to a patient’s treatment regimen are effective. If a patient’s fructosamine is increased, then the patient’s average glucose over the last 2 to 3 weeks has been elevated. In general, the higher the fructosamine concentration the higher the average blood glucose level.
Microalbuminuria occurs when the kidney leaks small amounts of albumin into the urine about 30 mg to 300 mg of albumin a day in the urine.
indications for investigation: The microalbumin test measures very small levels of protein in the urine and may indicate a risk for developing kidney disease. The random microalbumin test or microalbumin/creatinine ratio is frequently ordered as a screening test on patients with chronic conditions, such as diabetes and hypertension, that put them at an increased risk of developing kidney failure.
Reference ranges: up to 20 μg/min. Levels between 20 and 200 μg/min or 30-300 mg/24h is microalbumin.
Result interpretation: Normal levels are an indication that kidney function is normal. Moderately increased microalbumin levels in urine indicate that a person is in one of the very early phases of developing kidney disease. Very high levels are an indication that kidney disease is present in a more severe form.
C-peptide is a compound of proinsulin molecule. It serves as an important linker between the A- and the B-chains of insulin and facilitates the efficient assembly, folding, and processing of insulin in the endoplasmic reticulum.