Glycosylated Hemoglobin Assay that Reflects Long-Term Glucose
Concentration
Protocol Id
140901
Version #
1
Description of
Protocol
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 for standardized
laboratory assays.
Specific
Instructions
The Diabetes Working Group notes that that there are now point of care
instruments for testing Glycosylated hemoglobin that may provide an
alternative to the protocol listed here.
Protocol Text
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
Note from the Diabetes Working Group: If more bioassays are being
performed, the Diabetes Working recommends using a 10-mL EDTA tube.
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 SP answer "No" or "Don’t Know," blood is drawn from the SP.
2. Have you received cancer chemotherapy in the past four weeks or do you
anticipate such therapy in the next four 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 SP answer "No" or "Don’t Know," blood is drawn from the SP.
Note from the Diabetes Working Group: The investigator should record the
reason a sample person is excluded from the blood draw.
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.
Note from the Diabetes Working Group: The Diabetes Working Group
recommends that the investigator record whether the blood was drawn and
whether the full amount was obtained.
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 50-1000μL 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.
Note from the Diabetes Working Group: The sample should be stored at 4°C
until testing and shipped with refrigerated packs.
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 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 Working Group recommends that no changes in the protocol be made
over the course of the study.
To aid comparability, the Diabetes Working Group recommends that the
investigator record the make and manufacturer of equipment used and the
repeatability and coefficients of variation for the assay.
Reference Ranges
Glycosylated hemoglobin ranges between 4.4 and 6.0% normally
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.
Source
Centers for Disease Control and Prevention (CDC). National Center for Health
Statistics (NCHS). 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, 2007.
Language
English, Spanish
Participant
Participants aged 12 years and older.
Personnel and
Training
Required
Phlebotomist, Laboratory that can perform the glycosylated hemoglobin test
Equipment Needs Phlebotomy supplies
Standards
General
References
Standard
Name
ID
Source
Common Data Elements
(CDE)
Hematology Glycosylated
3049798 CDE Browser
Hemoglobin Measurement Lab
Percentage Value
Logical Observation
Identifiers Names and
Codes (LOINC)
Glycosylated hemoglobin assay 62854-5 LOINC
American Diabetes Association. (2009). Standards of medical care in diabetes
- 2009. Diabetes Care, 31(Supplement 1), S13 - S61.
American Diabetes Association. (2010). Diagnosis and classification of
diabetes mellitus. Diabetes Care, 33 (Supplement 1), S11 - S61
Protocol Type
Bioassay
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. (2010). Diagnosis and classification of
diabetes mellitus. Diabetes Care, 33 (Supplement 1), S11 - S61.
Requirements
Requirement Category
Required
Average time of greater than 15 minutes in an unaffected individual
No
Average time of greater than 15 minutes in an unaffected
individual
Major equipment
No
This measure requires a specialized measurement device that
may not be readily available in every setting where genome wide
association studies are being conducted. Examples of specialized
equipment are DEXA, Echocardiography, and Spirometry
Specialized requirements for biospecimen collection
No
This protocol requires that blood, urine, etc. be collected from
the study participants.
Specialized training
This measure requires staff training in the protocol methodology
and/or in the conduct of the data analysis.
No