Week Nine

Section: Special Chemistry. (COBAS)

Hi, I shall talk about this section whereby the analyzer used is called COBAS c system. The tests usually done here are Acute Myocardial Infarction (AMI) Panel; CKMB mass and Troponin T. Other tests include hormones and HbA1c.

I shall elaborate more on HbA1c. HbA1c is one of the glycated hemoglobins. It is formed in a two steps non-enzymatic reactions of glucose with the N-terminal amino group of the -chain of the normal adult Hb (HbA). The amount of HbA converted to HbA1c is relative to that of the average concentration of glucose in the blood thus, HbA1c is suitable to monitor long term blood glucose control in individuals with diabetes mellitus.

This method uses a detergent in the hemolyzing reagent to eliminate interface from leukocytes. All glycated hemoglobins at the -chain N-terminus and which have antibody-recognizable regions identical to that of HbA1c are measured.
The sample which comes in EDTA tube is to check for clotted blood. If there is no clotted blood, the presence of bubbles is removed to avoid sampling error. The sample is the placed in a special HbA1c rack and placed into the machine. The machine will detect the barcode and do the test ordered. The sample (glycohemoglobin in HbA1c) is reacted with anti-HbA1c antibody to form antigen-antibody complexes. Then, polyhaptens are added to start the reaction by reacting with the excess anti-HbA1c antibodies to form an insoluble antibody-polyhapten complex which is the measure turbidimetrically. The final result is expressed as percent HbA1c. The results are then transmitted to the LIS system and the staffs allocated there will validate the results.

nyzah