Haemoglobin Denaturant Reagent assay

• Format
  Liquid ready-to-use
• Assay Range
  0.25 - 2.4g/dl
• Working Stability 2-8 °C
  Stable to expiry

Intended Use

A Haemoglobin A1c test system is a device intended for the quantitative in vitro determination of Haemoglobin A1c concentration in whole blood. This product is suitable for use on RX series instruments which includes the RX daytona and RX imola analysers.

Clinical Significance

The measurement of HbA1c is used in the long-term monitoring of diabetes mellitus. This assay should not be used in the diagnosis of diabetes mellitus or for day to day glucose monitoring.

Diabetes Mellitus is a disease associated with poor glycaemic control. Numerous clinical studies, including the Diabetes Control and Complications Trial, have shown that diabetes related complications may be reduced by the long term monitoring and tight control of blood glucose levels.

In the diabetic patient where blood glucose levels are abnormally elevated the level of HbA1c also increases, the reason for this is that HbA1c is formed by the nonenzymatic glycation of the N-terminus of the -chain of haemoglobin A0.

The level of HbA1c is proportional to the level of glucose in the blood and has been widely accepted as an indicator of the mean daily blood glucose concentration over the preceding 6-8 weeks. It is therefore, a long term indicator of diabetic control, whereas, the measurement of blood glucose is only a short term indicator.

Principle

Both the concentration of HbA1c and the concentration of total haemoglobin are measured. The reported HbA1c result is calculated as a % of the total haemoglobin concentration. The HbA1c and total haemoglobin values generated in this assay are intended for use in the calculation of the HbA1c/total haemoglobin ratio (%HbA1c) and must not be used individually for diagnostic purposes.

In some methods falsely elevated % HbA1c results can be caused by the labile fraction of glycated haemoglobin (Schiff base). However this assay is not affected by “labile HbA1c” as the antibody used is specific for HbA1c (a stable ketamine).

(a) Sample Pre-treatment

The first step of the procedure involves the pre-treatment of the whole blood sample. This lyses red blood cells and causes hydrolysis of the haemoglobin by the action of a protease enzyme in the Haemoglobin Denaturant Reagent.

(b) Determination of Total Haemoglobin

The Total Haemoglobin reagent is used to determine the concentration of total haemoglobin. The method involves the conversion of all the haemoglobin derivatives into haematin in an alkaline solution of a non-ionic detergent as described by Wolf et al (1984).

The reaction is initiated by the addition of the pre-treated sample to the total haemoglobin reagent, resulting in a green solution. The conversion of different haemoglobin species into alkaline haematin with one defined absorption spectrum allows the endpoint measurement of total haemoglobin at 600 nm.

(c) Determination of HbA1c

The determination of HbA1c is based on a latex agglutination inhibition assay.

The agglutinator, which consists of a synthetic polymer containing multiple copies of the immunoreactive portion of HbA1c, causes agglutination of latex coated with HbA1c specific mouse monoclonal antibodies.

In the absence of HbA1c in the sample, the agglutinator in the HbA1c R2 Reagent and the antibody-coated micro particles in the HbA1c R1 Reagent will agglutinate, resulting in an increase in absorbance.

The presence of HbA1c in the sample will slow the rate of agglutination as it competes with the HbA1c agglutinator for antibody binding sites on the latex.

Hence, the increase in absorbance is inversely proportional to the concentration of HbA1c in the sample.

An increase in absorbance due to agglutination is measured at 700 nm and the extent of agglutination is used to calculate the concentration of HbA1c from a Calibration Curve. The percentage HbA1c is then calculated using the g/dl HbA1c and Total Haemoglobin values.

Available Applications

RX series instruments, including:

RX daytona

RX imola