Protocol - Glycosylated Hemoglobin - Assay
- Fasting Plasma Glucose - Blood Draw
- Fasting Plasma Glucose - Glucometer
- Height - Knee Height
- Oral Glucose Tolerance Test
Description
This protocol provides instructions for drawing, processing, and storing blood for the hemoglobin A1c assay according to the National Health and Nutrition Examination Survey (NHANES) methods. Toolkit users are referred to the National Glycohemoglobin Standardization Program (NGSP) for standardized laboratory assays.
Specific Instructions
Note from the Diabetes Working Group (WG): If more bioassays are being performed, the Diabetes WG recommends using a 10 mL EDTA tube.
Note from the Diabetes WG: The Diabetes WG recommends that the investigator record whether the blood was drawn and whether the full amount was obtained.
Note from the Diabetes WG: The sample should be stored at 4°C until testing and shipped with refrigerated packs.
Note from the Diabetes WG: The investigator should record the reason a sample person is excluded from the blood draw.
To aid comparability, the Diabetes WG recommends that the investigator record the make and manufacturer of equipment used and the repeatability and coefficients of variation for the assay.
Note from the Expert Review Panel (ERP): Plasma or Serum
Collection of blood samples for the measurement of analytes requires a general determination of whether to use serum or plasma for the assay and also a determination of the type of collection tube to be obtained. For example, if plasma is to be used, a determination needs to be made as to whether EDTA- or heparin-containing collection tubes are used. While comparable values are obtained for many analytes from either serum or plasma, there may be situations where differences are more pronounced and serum- or plasma-specific norms will be needed for references. The protocol presented here uses EDTA plasma. At times, it may be possible to collect both, but other considerations, such as participant burden, may be the deciding factor. It is important to match assay type with sample type. Some automated devices may preclude the use of EDTA plasma, for example, while others may be optimized for it. Investigators should choose methods of collection that match the methods of analysis. This will best be done by communicating with the laboratory where the proposed assays will be performed. They will become an important partner with you in assuring that there is compatibility from collection to assays to interpretation and reporting of levels and results.
Note from the ERP: Hemoglobinopathies (e.g., sickle cell anemia) and other disorders which affect the half-life of red blood cells can alter the level of hemoglobin A1c, thus reducing its utility in these settings.
Note from the ERP: Hemoglobin A1C Point of Care
Numerous point-of-care devices are now available for determining hemoglobin A1c in the clinic at the time of examination, and some have been certified by the NGSP (formerly the National Glycohemoglobin Standardization Program). The immediate feedback offers numerous advantages, although it may come at a cost of precision. Using such devices may facilitate studies. If a point-of-care device is used, it is recommended that it be a device certified by the NGSP, which is supported by the National Institutes of Diabetes and Digestive and Kidney Diseases (NIDDK) (www.ngsp.org), and that all manufacturer recommendations be followed. Point-of-care devices, however, would generally not serve as a substitute for a centralized laboratory in the conduct of multi-centered studies.
The Sickle Cell Disease Curative Therapy Working Group notes that the American Diabetes association recommends monitoring glycemic control by serum fructosamine in patients with hemolytic anemias, including sickle cell disease.
Availability
Protocol
The following is a summary version of the full National Health and Nutrition Examination Survey 2007-2008 protocol.
The full National Health and Nutrition Examination Survey 2007-2008 Glycohemoglobin (HbA1C) test is part of the Laboratory Procedures Manual which can be found here: 2007-2008 NHANES Lab Manual.
The National Health and Nutrition Examination Survey protocol lists the following specifications for the Glycohemoglobin (HbA1C) test on page 8-3 of the Laboratory Manual:
Sample (mL): 0.4
Sample type: Whole Blood
Collection type: 4 mL EDTA
Vessel type: 2 mL
Remarks: Refrigerate
Exclusion Criteria
Persons will be excluded from this component if they:
• Report that they have hemophilia; or
• Report that they have received cancer chemotherapy in the last 4 weeks
SP = Sample Person.
1. Do you have hemophilia?
1 [ ] Yes
2 [ ] No
7 [ ] Refused
9 [ ] Don’t Know
If the SP answers "Yes," the SP is excluded from the blood draw. If the SP answers "No" or "Don’t Know," blood is drawn from the SP.
2. Have you received cancer chemotherapy in the past 4 weeks or do you anticipate such therapy in the next 4 weeks?
1 [ ] Yes
2 [ ] No
7 [ ] Refused
9 [ ] Don’t Know
If the SP answers "Yes," the SP is excluded from the blood draw. If the SP answers "No" or "Don’t Know," blood is drawn from the SP.
Venipuncture
Venipuncture should generally be performed using the median cubital, cephalic, or basilic veins in the left arm unless this arm is unsuitable. If the veins in the left arm are unsuitable, look for suitable veins on the right arm. If the veins in the antecubital space on both arms are not suitable, then look for veins in the forearm or dorsal side of the hand on the left arm/hand and then the right arm/hand.
Editor’s Note: Please review chapter 4 of the Laboratory Procedures Manual from the National Health and Nutrition Examination Survey for a full description of Phlebotomy procedures. 2007-2008 NHANES Lab Manual.
Recording the Results of the Venipuncture Procedure
Immediately after completing the venipuncture, record the results of the blood draw, the reasons for a tube not being drawn according to the protocol, and any comments about the venipuncture.
Process the Sample for the Glycosylated Hemoglobin Assay
Note: If the EDTA tube is clotted, do not process the HbA1C vessel.
• Invert the appropriate EDTA tube several times to remix contents thoroughly.
• Use trace-metal-free pipette tips and the 50-1,000 μL Eppendorf pipette to aliquot 0.4 mL whole blood for vessel 4 (Glycohem) on primary SPs aged 12+ into a 2 mL vessel.
• Securely close all vessels to prevent leakage and evaporation.
• Store specimen in a refrigerator at 4°C until the sample is tested.
Laboratory Assay for Glycosylated Hemoglobin
There are now many laboratory assays that have been certified by the National Glycohemoglobin Standardization Program (NGSP). The Diabetes Working Group (WG) recommends that Toolkit users review the National Glycohemoglobin Standardization Program (NGSP) website to select an appropriate assay that is standardized to the Diabetes Control and Complications Trial (DCCT). Once an assay is chosen for a particular study, the WG recommends that no changes in the protocol be made over the course of the study.
Reference Ranges
Glycosylated hemoglobin ranges between 4.4% and 6.0% normally
Personnel and Training Required
Phlebotomist and laboratory that can perform the glycosylated hemoglobin test. Staff trained to use point-of-care devices
Equipment Needs
Phlebotomy supplies; point-of-care devices
Requirements
| Requirement Category | Required |
|---|---|
| Major equipment | No |
| Specialized training | No |
| Specialized requirements for biospecimen collection | No |
| Average time of greater than 15 minutes in an unaffected individual | No |
Mode of Administration
Bioassay
Lifestage
Child, Adolescent, Adult, Senior
Participants
Participant aged 12 years and older
(The lower age limit in National Health and Nutrition Examination Survey [NHANES] was determined based on logistical considerations. The Expert Review Panel said that the assay may be used for ages less than 12 years.)
Selection Rationale
The National Health and Nutrition Examination Survey (NHANES) 2007-2008 protocol was selected as the best practice standardized methodology for blood collection, processing, and storage.
Language
Chinese, English, Other languages available at source
Standards
| Standard | Name | ID | Source |
|---|---|---|---|
| Logical Observation Identifiers Names and Codes (LOINC) | Glycosylated hemoglobin assay | 62854-5 | LOINC |
| Human Phenotype Ontology | Elevated hemoglobin A1c | HP:0040217 | HPO |
| caDSR Form | PhenX PX140901 - Glycosylated Hemoglobin Assay That Reflects Longterm Gl | 6169315 | caDSR Form |
Derived Variables
The threshold Glycosylated hemoglobin values for the scoring (+/-) of prediabetes and diabetes are updated yearly by the American Diabetes Association and can be found in the journal Diabetes Care. Prediabetes: Glycosylated hemoglobin between 5.7% and 6.4% Diabetes: Glycosylated hemoglobin greater than or equal to 6.5% American Diabetes Association. (2014). Diagnosis and classification of diabetes mellitus. Diabetes Care, 37(Suppl. 1), S81-S90.
Process and Review
The Expert Review Panel #1 reviewed the measures in the Anthropometrics, Diabetes, Physical Activity and Physical Fitness, and Nutrition and Dietary Supplements domains.
Guidance from the ERP includes:
• Changed name of measure
• Added recommendations on use of serum or plasma
Back-compatible: no changes to Data Dictionary
Previous version in Toolkit archive (link)
Protocol Name from Source
National Health and Nutrition Examination Survey (NHANES), Oral Glucose Tolerance Test (OGTT) Manual, 2007-2008
Source
Centers for Disease Control and Prevention (CDC), National Center for Health Statistics (NCHS). (2007). National Health and Nutrition Examination Survey Questionnaire. Laboratory Procedures Manual. Hyattsville, MD: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention.
General References
American Diabetes Association (ADA). (2014a). Diagnosis and classification of diabetes mellitus. Diabetes Care, 37(Suppl. 1), S81-S90.
American Diabetes Association (ADA). (2014b). Standards of medical care in diabetes-2014. Diabetes Care, 37(Suppl. 1), S14-S80.
Behan, K. J., & Mershen, J. (2011). HbA1c does not always estimate average glucose. Clinical Laboratory Science, 24(2), 71-77.
Miles, R. R., Roberts, R. F., Putnam, A. R., & Roberts, W. L. (2004). Comparison of serum and heparinized plasma samples for measurement of chemistry analytes [Letter to the Editor]. Clinical Chemistry, 50(9), 1704-1705.
Protocol ID
140901
Variables
Export Variables| Variable Name | Variable ID | Variable Description | dbGaP Mapping | |
|---|---|---|---|---|
| PX140901_Assay_Repeatability | ||||
| PX140901080000 | Repeatability of the assay | N/A | ||
| PX140901_Assay_Type | ||||
| PX140901060000 | Record the type of assay used to perform the more | N/A | ||
| PX140901_Blood_Draw_Comments | ||||
| PX140901040200 | Record any comments about the blood draw, more | Variable Mapping | ||
| PX140901_Blood_Draw_Done | ||||
| PX140901040000 | Was blood drawn? | Variable Mapping | ||
| PX140901_Blood_Draw_Sample | ||||
| PX140901040100 | Was full sample obtained? | N/A | ||
| PX140901_Chemotherapy | ||||
| PX140901020000 | Have you received cancer chemotherapy in the more | Variable Mapping | ||
| PX140901_Coefficient_Of_Variation | ||||
| PX140901090000 | Coefficient of variation for the assay | N/A | ||
| PX140901_Equipment_Make_Manufacturer | ||||
| PX140901070000 | Make and manufacturer of the equipment used more | N/A | ||
| PX140901_Exclusion_Criteria | ||||
| PX140901030000 | Exclusion Criteria | N/A | ||
| PX140901_Hemophilia | ||||
| PX140901010000 | Do you have hemophilia? (exclusion from more | Variable Mapping | ||
| PX140901_Percent_Glycosylated_Hemoglobin | ||||
| PX140901100000 | Percent Glycosylated Hemoglobin | N/A | ||
| PX140901_Sample_Comments | ||||
| PX140901050000 | Record any comments about the blood during more | Variable Mapping | ||
Measure Name
Glycosylated Hemoglobin Assay
Release Date
May 10, 2010
Definition
A bioassay to measure percent glycosylated hemoglobin (Glycohemoglobin, Hemoglobin A1C, A1C), or the amount of glucose attached to the hemoglobin in red blood cells (ADA, 2014a).
Purpose
Glycosylated hemoglobin is a well-recognized assay of blood glucose concentration over the preceding several months, and results are predictive of diabetes complications and outcomes. The glycosylated hemoglobin assay can also be used as a diagnostic criterion for diabetes (ADA, 2014a).
Keywords
diabetes, hyperglycemia, glycohemoglobin, glycosylated hemoglobin, hemoglobin, A1C, metabolic syndrome, NHANES
Measure Protocols
| Protocol ID | Protocol Name |
|---|---|
| 140901 | Glycosylated Hemoglobin - Assay |
Publications
There are no publications listed for this protocol.