Table of Contents

Component Description

The Thyroid Profile consists of a battery of several tests for the measurement of thyroid function, including Total and Free Thyroxine, Total and Free Triiodothyronine, Thyroglobulin, Thyroglobulin Antibodies, Thyroid Peroxidase Antibodies, and Thyroid Stimulating Hormone. Thyroid function is crucial for maintaining normal metabolic function in adults and for proper neurological development of the fetus. Serum levels will be used to assess thyroid function and will provide population-based reference information on these hormone levels

Eligible Sample

Participants aged 12 years and older, who do not meet any of the exclusion criteria, are eligible.

Description of Laboratory Methodology

Thyroid blood specimens were processed, stored and shipped to University of Washington, Seattle, WA. Detailed specimen collection and processing instructions are discussed in the NHANES Laboratory/Medical Technologists Procedures Manual (LPM).

Thyroid-stimulating hormone

The Access HYPERsensitive human thyroid-stimulating hormone (hTSH) assay is a 3rd generation, two-site immunoenzymatic (“sandwich”) assay. A sample is added to a reaction vessel with goat anti-hTSH-alkaline phosphatase conjugate, buffered protein solution, and paramagnetic particles coated with immobilized mouse monoclonal anti-hTSH antibody. (Goat anti-mouse antibody is used to immobilize the mouse anti-hTSH antibody.) The hTSH binds to the immobilized monoclonal anti-hTSH on the solid phase while the goat anti-hTSH-alkaline phosphatase conjugate reacts with a different antigenic site on the hTSH. After incubation in a reaction vessel, materials bound to the solid phase are held in a magnetic field while unbound materials are washed away. Then, the chemiluminescent substrate Lumi-Phos™ 530 is added to the vessel and light generated by the reaction is measured with a luminometer. The light production is directly proportional to the concentration of human thyroid-stimulating hormone in the sample. The amount of analyte in the sample is determined from a stored, multi-point calibration curve.

Human TSH is one of several glycoprotein hormones consisting of two non-covalently bound peptide chains: an a-chain, which is nearly identical in all, and a ß-chain, which is responsible for immunological and biological specificity. These similarities result in varying degrees of cross-reactivity of different antisera. The Access HYPERsensitive hTSH assay has virtually no cross-reactivity with other peptide hormones. The sensitivity and specificity of this test enable better discrimination between hyperthyroid and euthyroid patients.

Total T3 assay

The Access Total T3 assay is a competitive binding immunoenzymatic assay. Sample is added to a reaction vessel with a stripping agent to dissociate T3 from the binding proteins. T3 in the sample competes with the T3 analogue coupled to biotin for anti-T3 alkaline phosphatase conjugate. Of the resulting antigen/antibody complexes, the T3 analogue/antibody complexes are bound to the streptavidin coated solid phase. Separation in a magnetic field and washing removes the sample T3/antibody complexes and other materials not bound to the solid phase. Then, the chemiluminescent substrate Lumi-Phos™ 530 is added to the vessel and light generated by the reaction is measured with a luminometer. The light production is inversely proportional to the concentration of total T3 in the sample. The amount of analyte in the sample is determined from a stored, multi-point calibration curve.

Free T3 assay

Access Free T3 assay is a competitive binding immunoenzymatic assay. A sample is added to a reaction vessel with an anti-T3 monoclonal antibody conjugated to alkaline phosphatase. During the incubation, free T3 in the sample reacts with the anti-T3 antibody. Particles coated with streptavidin and biotinylated T3 analog are then added to the mixture. Unoccupied binding sites on the anti-T3 antibody are bridged to the particle through the T3 analog. After incubation in a reaction vessel, materials bound to the solid phase are held in a magnetic field while unbound materials are washed away. Then, the chemiluminescent substrate Lumi-Phos™ 530 is added to the vessel and light generated by the reaction is measured with a luminometer. The light production is inversely proportional to the concentration of free T3 in the sample. The amount of analyte in the sample is determined from a stored, multi-point calibration curve.

Total T4 assay

The Access Total T4 assay is a competitive binding immunoenzymatic assay. A sample is added to a reaction vessel with anti-thyroxine antibody, thyroxine-alkaline phosphatase conjugate, and paramagnetic particles coated with goat anti-mouse capture antibody and a stripping agent to dissociate all T4 from binding proteins. Thyroxine in the sample competes with the thyroxine-alkaline phosphatase conjugate for binding sites on a limited amount of specific anti-thyroxine antibody. Resulting antigen: antibody complexes bind to the capture antibody on the solid phase. After incubation in a reaction vessel, materials bound to the solid phase are held in a magnetic field while unbound materials are washed away. Then, the chemiluminescent substrate Lumi-Phos™ 530 is added to the vessel and light generated by the reaction is measured with a luminometer. The light production is inversely proportional to the concentration of thyroxine in the sample. The amount of analyte in the sample is determined from a stored, multi-point calibration curve.

Free T4 assay

The Access Free T4 (FRT4) assay is a two-step enzyme immunoassay. Monoclonal anti-Thyroxine (T4) antibody coupled to biotin, sample, buffered protein solution, and streptavidin-coated solid phase are added to the reaction vessel. During this first incubation, the anti-T4 antibody coupled to biotin binds to the solid phase and the free T4 in the sample. After incubation in a reaction vessel, materials bound to the solid phase are held in a magnetic field while unbound materials are washed away. Next, buffered protein solution and triiodothyronine (T3)-alkaline phosphatase conjugate are added to the reaction vessel. The T3-alkaline phosphatase conjugate binds to the vacant anti-T4 antibody binding sites. After incubation in a reaction vessel, materials bound to the solid phase are held in a magnetic field while unbound materials are washed away. Then, the chemiluminescent substrate Lumi-Phos™ 530 is added to the vessel and light generated by the reaction is measured with a luminometer. The light production is inversely proportional to the concentration of free T4 in the sample. The amount of analyte in the sample is determined from a stored, multi-point calibration curve.

Thyroglobulin (Tg) assay

The Access thyroglobulin (Tg) assay is a simultaneous one-step "sandwich" assay. A sample is added to a reaction vessel, along with biotinylated mixture of four monoclonal anti-Tg antibodies, streptavidin coated paramagnetic particles, and monoclonal anti-Tg antibody alkaline phosphatase conjugate. The biotinylated antibodies and the serum or plasma thyroglobulin bind to the solid phase, while the conjugate antibody reacts with a different antigenic site on the thyroglobulin molecule. After incubation in a reaction vessel, materials bound to the solid phase are held in a magnetic field while unbound materials are washed away. A chemiluminescent substrate, Lumi-Phos** 530 is added to the reaction vessel and light generated by the reaction is measured with a luminometer. The light production is directly proportional to the concentration of thyroglobulin in the sample. The amount of Thyroglobulin in the sample is determined by means of a stored, multi-point calibration curve.

Thyroglobulin antibody assay (TgAb)

The Access thyroglobulin antibody assay is a sequential two-step immunoenzymatic "sandwich" assay. A sample is added to a reaction vessel with paramagnetic particles coated with the thyroglobulin protein. After incubation, materials bound to the solid phase are held in a magnetic field while unbound materials are washed away. The thyroglobulin-alkaline phosphatase conjugate is added and binds to the TgAb. After a second incubation, the reaction vessel is washed to remove unbound materials. A chemiluminescent substrate, Lumi-Phos™ 530 is added to the reaction vessel and light generated by the reaction is measured with a luminometer. The light production is proportional to the concentration of Thyroglobulin antibody in the sample. The amount of Thyroglobulin antibody in the sample is determined by means of a stored, multi-point calibration curve.

Thyroid peroxidase antibody

The Access TPO antibody (TPOAb) assay is a sequential two-step immunoenzymatic "sandwich" assay. A sample is added to a reaction vessel with paramagnetic particles coated with the thyroid peroxidase protein. After an incubation, materials bound to the solid phase are held in a magnetic field while unbound materials are washed away. The protein A-alkaline phosphatase conjugate is added and binds to the TPOAb. After a second incubation, the reaction vessel is washed to remove unbound materials. A chemiluminescent substrate, Lumi-Phos™ 530 is added to the reaction vessel and light generated by the reaction is measured with a luminometer. The light production is proportional to the concentration of TPO antibody in the sample. The amount of TPOAb in the sample is determined by means of a stored, multi-point calibration curve.

Data Processing and Editing

Read the General Documentation on Laboratory Data file for detailed data processing and editing protocols. The analytical methods are described in the Description of the Laboratory Methodology section.

Laboratory Quality Assurance and Monitoring

The NHANES quality control and quality assurance protocols (QA/QC) meet the 1988 Clinical Laboratory Improvement Amendments mandates. Detailed quality control and quality assurance instructions are discussed in the NHANES LPM. Read the General Documentation on Laboratory Data file for detailed QA/QC protocols.

A detailed description of the quality assurance and quality control procedures can be found on the NHANES website.

Analytic Notes

The analysis of NHANES 2001–2002 laboratory data must be conducted with the key survey design and basic demographic variables. The NHANES 2001–2002 Household Questionnaire Data Files contain demographic data, health indicators, and other related information collected during household interviews. They also contain all survey design variables and sample weights for these age groups. The phlebotomy file includes auxiliary information such as the conditions precluding venipuncture. The household questionnaire and phlebotomy files may be linked to the laboratory data file using the unique survey participant identifier SEQN.

Exam sample weights should be used for analyses. Please refer to the Analytic Guidelines for further details on the use of sample weights and other analytic issues. The Analytic Guidelines are available on the NHANES website.

Codebook and Frequencies

SEQN - Respondent sequence number

Variable Name:
SEQN
SAS Label:
Respondent sequence number
English Text:
Respondent sequence number.
Target:
Both males and females 12 YEARS - 150 YEARS

SSATG - Thyroglobulin antibody

Variable Name:
SSATG
SAS Label:
Thyroglobulin antibody
English Text:
Thyroglobulin antibody
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.6 to 1930.6 Range of Values 2004 2004
. Missing 6 2010

SST3F - Free T3

Variable Name:
SST3F
SAS Label:
Free T3
English Text:
Free T3
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1.6 to 21.8 Range of Values 2009 2009
. Missing 1 2010

SST4F - Free T4

Variable Name:
SST4F
SAS Label:
Free T4
English Text:
Free T4
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.1 to 4.8 Range of Values 2009 2009
. Missing 1 2010

SSTGN - Thyroglobulin

Variable Name:
SSTGN
SAS Label:
Thyroglobulin
English Text:
Thyroglobulin
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.07 to 828.94 Range of Values 2009 2009
. Missing 1 2010

SSTPO - Thyroperoxidase antibody

Variable Name:
SSTPO
SAS Label:
Thyroperoxidase antibody
English Text:
Thyroperoxidase antibody
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.1 to 964.2 Range of Values 1993 1993
. Missing 17 2010

SSTSH1 - Thyroid stimulating hormone

Variable Name:
SSTSH1
SAS Label:
Thyroid stimulating hormone
English Text:
Thyroid stimulating hormone
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.002 to 350.517 Range of Values 2004 2004
. Missing 6 2010

SSTT3 - Total T3

Variable Name:
SSTT3
SAS Label:
Total T3
English Text:
Total T3
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
30 to 514 Range of Values 2009 2009
. Missing 1 2010

SSTT4 - Total T4

Variable Name:
SSTT4
SAS Label:
Total T4
English Text:
Total T4
Target:
Both males and females 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.5 to 24.7 Range of Values 2009 2009
. Missing 1 2010