Glycosylated Hemoglobin A1c (HbA1c)

Transcription

1 APPROVED BY:... DR WAN MOHD IZANI WAN MOHAMED ENDOCRINE LABORATORY DIRECTOR CONTROLLED COPY NO: 0 REGISTERED HOLDER ENDOCRINOLOGY LABORATORY Glycosylated Hemoglobin A1c (HbA1c) PREPARED BY DESIGNATION : MUHAMMAD AMALI BIN KAMARUDIN : QUALITY MANAGER / SCIENCE OFFICER : AINUN IZZATI RAZALI : DOCUMENT CONTROLLER : AFIQAH IYLIA AB HALIM : DEPUTY DOCUMENT CONTROLLER CHECKED BY DESIGNATION AUTHORISED BY DESIGNATION : MUHAMMAD AMALI BIN KAMARUDIN : ENDOCRINE LABORATORY DEPUTY DIRECTOR/QUALITY MANAGER : DR WAN MOHD IZANI BIN WAN MOHAMED : ENDOCRINE LABORATORY DIRECTOR Page 1 of 18

2 1. CONTENT NO. CONTENT PAGE 1 Content 2 2 Record of Review 3 3 Record of Amendments 4 4 Objective, method, test principle 5 5 Clinical significance 6 6 Requirements Procedure Limitation / source of error 18 9 Limits and Ranges References 18 Page 2 of 18

3 2. RECORD OF REVIEW No semakan Tarikh semakan Nama Penyemak 1 22/01/2014 Muhammad Amali b Kamarudin 2 08/09/2014 Ainun Izzati Razali Tandatangan pengesahan Page 3 of 18

4 3. RECORD OF AMMENDMENT DATE VERSION NO DETAIL OF AMMENDMENT 14/09/ Page 10/19 Prosedur Installing the update kit floppy diskette 15/09/ Page 11/19 : Install New Elution Buffer and wash /diluents solution-pembuangan prosedur D-10 + Rack loader 15/09/ Page 12/18: Priming A New Cartrige- pembuangan prosedur D Rack loader 15/09/ Page 13/18: Calibration - pembuangan prosedur D-10 + Rack loader 15/09/ Page 17/18: Add : (INTERPRETATION OF RESULT) BY Izzati Izzati Izzati Izzati Izzati Page 4 of 18

5 4. OBJECTIVE Standard technical manual to determine the percent of hemoglobin A1c in human whole blood using Cation-exchange High Performance Liquid Chromatography (HPLC) Bio-Rad D METHOD Automated D-10 Hemoglobin Testing System based on these methods: 2.1 Cation-exchange High Performance Liquid Chromatography (HPLC) 6. PRINCIPLE OF THE PROCEDURE The D-10 utilizes principles of ion-exchange high-performance liquid chromatography (HPLC). The samples are automatically diluted and injected into the analytical cartridge. The D-10 delivers a programmed buffer gradient of increasing ionic strength to the cartridge. The hemoglobins are separated based on their ionic interactions with the cartridge material. The separated hemoglobins then pass through the flow cell of the filter photometer, where changes in the absorbance at 415 nm are measured. Page 5 of 18

6 7. CLINICAL SIGNIFICANCE Diabetes mellitus is a condition characterized by hyperglycemia resulting the body s inability to use blood glucose for energy. In type 1 diabetes, the pancrease no longer make insulin and therefore, blood glucose cannot enter the cell to be used for energy. In Type 2 Diabetes, either the pancrease does not make enough insulin or the body is unable to use insulin correctly. The direct and indirect effects of hyperglycemia on the human vascular system are the major source of morbidity and mortality in both Type 1 and Type 2 Diabetes. These effect include macrovascular complications (coronary artery disease, peripheral arterial disease, and stroke) and microvascular complications (diabetic nephropathy, neuropathy and retinopathy). Diabetus mellitus affects approximately 7% of the world population. Therapy for diabetes requires the long term maintainance of a blood glucose level as possible to a normal level., minimizing the risk of long-term vascular consequences. A single fasting blood glucose measurement is an indication of the patient s immediate past condition (hours), but may not represent the true status of blood glucose regulation. The measurement of hemoglobin A1c ( HbA1c) every two to three months has been accepted as a measure of glycemic control in the care and treatment of patients with diabetes mellitus. HbA1c, the glycohemoglobin of interest, is formed in two steps by the non enzymatic glycation of HbA. The first step is formation of an unstable aldimine (labile A1c, or pre-a1c), a reversible reaction between the carbonyl group of glucose and N terminal valine of the b- chain of hemoglobin. Labile A1c formation is directly proportional to the blood glucose concentration. During the red blood cell circulation, some of the labile A1c is converted (Amodori rearrangement) to form a stable ketoamine, HbA1c. The D-10 Hemoglobin A1c Program is based on chromographic separation of HbA1c on a cation exchange cartridge. Separation is optimized to minimize interference form hemoglobin variants, labile A1c, and carbamylated hemoglobin. Please refer to limitation of the Procedure and Performance Characteristics for more information. The D-10 Hemoglobin A1c Program also offers automatic sampling from a primary whole blood tube, followed by sample dilution, and an analysis time of three minutes per sample. Page 6 of 18

7 8. REQUIREMENTS 8.1 EQUIPMENT Bio-Rad D-10 Hemoglobin Testing System 8.2 KIT COMPONENTS D-10 Hemoglobin A1c Reorder Pack The reorder pack contains supplies for 400 tests: REFERENCE DESCRIPTION CAPACITY EXPLAINATION Elution Buffer ml Elution Buffer ml Wash/Diluent Solution Analytical Cartridge Calibrator/Diluent Set Whole Blood Primer Sample Vials 1600 ml One cation exchange cartridge Three vials of Calibrator Four vials of lyophilized human red blood cell 100 polypropylene vials Two bottles containing 2000 ml of a Bis Tris/Phosphate buffer, ph 6.0. Contains <0.05% sodium azide as a preservative. One bottle containing 1000 ml of a Bis Tris/Phosphate buffer, ph 6.7. Contains <0.05% sodium azide as a preservative. One bottle containing 1600 ml of deionized water with <0.05% sodium azide as a preservative. One cation exchange cartridge, 4.0 mm ID x 30 mm. One set consisting of three vials of Calibrator Level 1, three vials of Calibrator Level 2, and one bottle of Calibrator Diluent. The calibrator vials contain lyophilized human red blood cell hemolysate with gentamicin, tobramycin, and EDTA as preservatives. Reconstituted volume is 7 ml per vial. Calibrator Diluent contains 100 ml of deionized water with <0.05% sodium azide as a preservative Four vials of lyophilized human red blood cell hemolysate with gentamicin, tobramycin, and EDTA as preservatives. Reconstituted volume is 1.0 ml per vial. 100 polypropylene vials with pierceable caps, 1.5 ml STORAGE (ºC) SHELF LIFE (days) room temperature Room Temperature D-10 Hemoglobin A1c Supplement Reagent Pack REFERENCE DESCRIPTION CAPACITY EXPLAINATION Elution Buffer ml Elution Buffer ml Wash/Diluent Solution 1600 ml Two bottles containing 2000 ml of a Bis Tris/Phosphate buffer, ph 6.0. Contains <0.05% sodium azide as a preservative. One bottle containing 1000 ml of a Bis Tris/Phosphate buffer, ph 6.7. Contains <0.05% sodium azide as a preservative. One bottle containing 1600 ml of deionized water with <0.05% sodium azide as a preservative. STORAGE (ºC) SHELF LIFE (days) Page 7 of 18

8 8.3 QUALITY CONTROL MATERIAL QC NAME CAPACITY PER VIAL Lyphocheck Diabetes Bi-Level Control Level 1 Level 2 6 x 0.5 ml 8.4 SPECIMEN Serum collected The whole blood specimens should be collected in a vacuum collection tube cantaining EDTA Specimen storage Temperature 2-3 ºC Room Temperature (15-30 ºC) Life 7 days 3 days Sample preparation Allow sample tube to reach room temperature (15-30 ºC) before performing the assay. No sample preparation is required. Mixing has no impact on HbA1c value as long as the total area is in range The sample tubes area loaded into the D-10 sample rack and placed in the D-10. Ensure that the sample barcodes are facing towards the back of the instrument Use special rack inserts for 12,13, and 14 mm diameter tubes. Remove all inserts for 16mm diameter tubes Tubes with the height of 75 mm to 100 mm are acceptable for use If the sample is in an abnormal size/type tube, or if there is less than 2.0 ml of sample im the tube, then the sample must be prediluted Before pipetting, thoroughly mix the sample by gently inverting the tube. To predilute, pipet 1.5 ml of wash /Diluent Solution into a labeled 1.5 ml vial, followed by 5 ul of whole blood sample Cap the sample vial and mix throughtly. Use the sample vial adapter for 1.5 ml vials. Page 8 of 18

9 9. PROCEDURE NO. ACTIVITY 9.1 SAMPLE PREPARATION Whole Bloo Primer. a. Reconstitute with 1 ml of distilled water. b. Allow to stand for minutes, swirl gently to dissolve c. This primer stable for 1 day at 2-8 ºC d. Priming of cartridge is done at least once for every cartridge RESPONSIBILITY HbA1c Calibrators a. 2 calibrator (Level 1 and Level 2) b. Reconstitute each vial with 7 ml cold calibrators Diluent c. Allow to stand for minutes and swirl gently to dissolve d. Transter 1 ml each of dissolved calibrators into the assigned 1.5 ml microvials e. This calibrator stable for 7 days at 2-8 ºC (after opened) Lyphocheck Controls (Lyphocheck Diabetes Bi-Level Control :Level 1 and Level 2) f. Reconstitute each vial with 0.5 ml of distilled water. g. Allow to stand for 5-10 minutes and swirl gently to dissolve h. Transter 5 ul ml each microvial. i. This control stable for 7 days at 2-8 ºC (after opened) Whole blood sample a. Sample should be collected in vacuum collection tubes containing EDTA. b. This sample stable for 7 days at 2-8 ºC or 3 days at room temperature (15-30 ºC) c. Allow sample tubes to reach room temperature ºC prior to analysis. No sample preparation required. d. If abnormal tube type or sample is less than 2 ml, then predilute 1:300 in a 1.5 ml sample vial (5 ul of control in 1.5 ml of wash/diluents solution) prior to analysis Page 9 of 18

10 NO. ACTIVITY Installing the update kit floppy diskette RESPONSIBILITY a. Go to LOT INFO screen. b. Insert floppy diskette. c. Press UPDATE KIT d. Follow the instructions on the screen to proceed with the Update Kit Procedure e. Remove the floppy diskette from the A;\drive once the procedure is completed. Page 10 of 18

11 NO. ACTIVITY 9.2 INSTALLING REAGENTS Install New Elution Buffer and wash /diluents solution RESPONSIBILITY a. Place the system in the sleep mode b. Remove the reagent bottles one at a time c. Do not touch the lines below the caps d. Do not wipe lines e. Place each bottle in a proper position on the reagent bottle tray f. After opening the bottles, the reagent are stable for 8 weeks at ºC g. The second bottle of Elution buffer 1 is installed at 200 injections h. Go to LOT INFO/Buffer 1 screen. i. Press the volume box to display the reset buffer volume screen h. Press reset Page 11 of 18

12 NO. ACTIVITY PRIMING A NEW CARTRIGE A priming run is performed once per new cartridge and also following the decontaimination procedure. a. The system should be in Standby mode. b. Pipet 1 ml of reconstituted Whole Blood Primer into a sample vial. c. Place the sample vial into a sample vial adapter labeled with a Primer barcode, then place the adapter into sample rack position, ensure the adapter magnet and barcode faces the back of the rack. The primer must be the only sample in the rack. RESPONSIBILITY NOTE: The priming run must be performed as a separated run. d. Insert the rack through the rack door. e. After the rack is finished loading, go to the RUN screen. f. Ensure the sample ID Prime appears in the worklist. If not, type Prime as the sample ID for position 1 using the keypad in the RUN/Edit screen. g. Press Done h. Press Start i. The entire priming sequence lasts 13 min. j. Press eject to remove the processed rack. Page 12 of 18

13 NO. ACTIVITY 9.3 CALIBRATION Calibration is performed after priming a new cartrige and as needed for troubleshooting RESPONSIBILITY a. The system should be in the Standby mode b. Place the following in a sample rack: Tube Adapter Label Reagent Position 1 Calibrator 1 HbA1c Calibrator, Level 1 (1 ml) 2 Calibrator 2 HbA1c Calibrator, Level 1 (1 ml) 3 A1c Low Control Control, Level 1 4 A1c High Control Control, Level NA Patient Samples c. Ensure the barcodes face the back of the rack. d. Ensure the Stop if calibration fails checkbox is selected in the SETTING/Alert Settings screen; if not, the run will continue after calibration failure, using the last acceptable slope and intercept. e. Insert the rack through the rack DOOR f. After the rack finished loading, go to the RUN screen. g. If necessary, enter sample IDs for missing barcodes using the keypad in the RUN/Edit screen. Press Done. h. Press Start i. The calibration report is printed after testing is complete. j. The slope and intercept acceptable ranges are provided in the Calibrator / Diluent Set Insert. k. Press Eject to remove the processed rack. Page 13 of 18

14 NO. ACTIVITY RESPONSIBILITY 9.4 DAILY MAINTAINTANCE Pre-Run Checklist Check that the correct ( HbA1c) is installed Check the buffer / wash levels, lot numbers, and line positions. Check reagent onboard expiration dates. Check cartridge injection count and lot number Check pump pressure with pump running (MAINTAIN screen): Flow rate at 1.5 ml, 50% buffer 2 Pump pressure should not fluctuate more than 5%. Prime the lines if needed. The expected pressure range using the cartridge is kg/cm2 Check for leaks during pressure check Check external waste tank level Check printer paper supply Routine Sample Run a. Place the following in a sample rack: TUBE POSITION ADAPTER LABEL REAGENT 1 A1c Low Control Control, Level 1(Optional) 2 A1c High Control Control, Level 2(Optional) 3 to N NA Patient samples b. Ensure the barcode face the back of the rack c. Insert the rack through the rack door d. After the rack is finished loading, go to the RUN screen. e. If necessary, enter sample IDs, for missing barcodes using the keypad in the RUN/Edit screen. Press Done. f. Press Start. g. Press Eject to remove the processed rack. Page 14 of 18

15 NO. ACTIVITY Acceptance Criteria RESPONSIBILITY ITEM Total Area range Quality control HbA1c reprtable range HbF Labile A1c Carbamylated hemoglobin (LA1c/ CHb- 2) Hemoglobin S trait and C trait. Variant window Variant, S and C windows CRITERIA 1.0 million to 5.0 million Results should not be reported if the area is outside this range; the sample should be manually prediluted and rerun For some high total area, high HbA1c samples (e.g., 15% or 140 mmo/mol HbA1c with 5 M total area), the A1c peak may elute outside of the established retention time window. Predilute to approximately 2.5 M total area and rerun Value should be in range NGSP : % IFCC : mmol/mol Results outside of this range should not be reported Any sample with >15% or >140 mmol/mol HbA1c should be suspected of having a hemoglobin variant. < 10% does not interfere with assay (LA1c/CHb-1) < 4% does not interfere with assay. < 3.5% does not interfere with assay HbA1c result is reportable If a peak appears in the variant window, the HbA1c result should not be reported. Combined area of > 60% should be suspected of having a homozygous variant or variant-bthalasessemia Phenotype; the HbA1c result should not be reported. Page 15 of 18

16 NO. ACTIVITY Review and Dispatching of Results RESPONSIBILITY Result review: Mark No ITEM OBSERVATION 1 Total Area 1.0 million to 5.0 million 2 A1c and A0 Peaks Correctly identified ed 3 A1c AND A0 retention times Consistently in range (refer to current cartridge insert for retention time windows 4 F peak <10% 5 LA1c/CHb-1 < 4% 6 HbA1c results Within reportable range 7 Baseline Properly instructed (i.e, stable, not drifting) 8 A1c Peak shape Sharp and symmetrical Page 16 of 18

17 NO. ACTIVITY INTERPRETATION OF RESULT Result Hb Variant Comment / Interpretation Hb Variant. Suspected present of Hb Variant No HbA1c Peak No HbA1c Peak. Variant of >60%, suspected of having a homozygous variant. Please use alternative method. Labile A1c high Labile A1c high. Possibility interference from LA1c. Please repeat with 2 nd sample. Labile A1c high (when repeat with 2nd sample) Hb F > 10% Labile A1c high (repeat sample). Possibility interference from LA1c. Please use alternative method. Hb F > 10%. Please use alternative method. Possibility of interference from HbF. RESPONSIBILITY Dispatch result : a. Release the results in LIS, put comment if required. b. Results are also kept in LIS database for traceability. Page 17 of 18

18 10. LIMITATION/SOURCES OF ERROR 10.1 Abnormal Red cell survival Sample from patients with hemolytic anemias will exhibit decreased glycated hemoglobin values due to the shortened life span of the red cells. This effect will depend upon the severity of the anemia. Samples from patients with polycythemia or post- splenectomy may exhibit increased glycated hemoglobin values due to a somewhat longer life span of the red cells Hemoglobin Variants HbA1c values determined using the Hemoglobin A1c Program HbS trait and HbC trait specimens showed no clinically significant difference from values determined by an NGSP certified boronate affinity method. Other abnormal hemoglobin variants have not been evaluated on the D-10 Hemoglobin A1c Program. For the positive confirmation of any particular hemoglobin variant, alternative separation methods are required. 11. Reference values Hemoglobin A1c (%) Degree of Glucose Control >8 Action suggested <7 Goal <6 Non-Diabetic Level Action suggested depends on individual patient circumstances which may include enhanced diabetes self-management education, co-management with a diabetes team, referral to an endocrinologist, change in pharmalogical theraphy, initiation or self-monitoring of blood glucose, or more frequent contact with the patient. 12. References 1. American Diabetes Association Home Page. (accessed Jan 2010) 2. Fowler, M.J. Microvascular and Macrovascular Complications of Diabetes. Clin Diabetes 2008,26(2), Shaw, J.E.; Sicree, R.A.; Zimmet, P.Z. Global Estimates of the Prevalence of Diabetes for 2010 and Diabetes Res. Clin. Pract.2010,87, Forsham, P.H. Diabetes Mellitus: A Rational Plan for Management. Postgrad. Med.1982,71, D-10 TM Hemoglobin A1c Program Instruction Manual 6. BIO-RAD Lyphochek Diabetes Control Level 1 and 2 (Package Insert) 7. Algorithm of Hb variants(kj Behan et al; Clinica Chimica Acta 406 (2009)124-8) Page 18 of 18