• Component Description
• Eligible Sample
• Description of Laboratory Methodology
• Data Processing and Editing
• Laboratory Quality Assurance and Monitoring
• Analytic Notes
• References
• Codebook
  • SEQN - Respondent sequence number
  • WTSSMC2Y - SSMUMP and SSCMV 2 year weights
  • WTSSMC4Y - SSMUMP and SSCMV 4 year weights 99-02
  • SSCMVOD - CMV optical density from ELISA
  • SSCMV - CMV specific IgG results
  • SSCMIGM - Cytomegalovirus IgM
  • SSCMIGGA - Cytomegalovirus IgG Avidity

National Health and Nutrition Examination Survey

1999-2000 Data Documentation, Codebook, and Frequencies

Cytomegalovirus Antibodies - Serum (Surplus) (SSCMV_A)

Data File: SSCMV_A.xpt

First Published: March 2008

Last Revised: April 2022

Component Description

Cytomegalovirus (CMV) antibody testing of stored sera specimens from NHANES 1999-2004 was conducted to estimate the seroprevalence of CMV infection (CMV IgG) in participants aged 6 to 49 years. An optical density measure for IgG is also included in this data release as an estimate of antibody titer.

CMV IgM and IgG avidity among CMV IgG positive samples might not only be helpful in examining the prevalence of IgM and low avidity, but also could provide opportunity of assessing their association with CMV urinary shedding, and the relative attribution to primary or non-primary infection.

Eligible Sample

Participants aged 6 to 49 years from NHANES 1999-2000 with stored sera.

Description of Laboratory Methodology

CMV specific IgG was measured with an ELISA by Quest International, Inc., Miami FL. Sera with values near the ELISA cutoff (approx 5.2% of total) were confirmed with a second ELISA assay by bioMerieux, Inc., Durham, NC. When the results from these 2 tests disagreed (approx. 2.7% of total), an IFA from Bion International, Inc., was used and the result of the IFA was given as the final result.

Optical Density for the IgG test is reported. Optical density was measured with the ELISA assay by Quest International, Inc. and approximately corresponds to antibody titer; a low and positive optical density indicates low antibody titer and a high optical density indicates high antibody titer.

Screening of specimens for CMV IgM was performed using ELISA assay by Diamedix, Miami Lakes, FL and the automated analyzer MAGO. Confirmatory testing for CMV IgM was performed on specimens within a wide range above and below the MAGO test cutoff using the VIDAS ELISA assay by bioMerieux, Inc., Durham, NC.

CMV IgG avidity was measured with an ELISA by bioMerieux, Inc., Durham, NC. (Dollard et al., 2011), 1= low avidity defined as RFV_INDEX < 0.7, 2= High avidity defined as RFV_INDEX ≥ 0.8, and 3= intermediate avidity defined as RFV_INDEX >0.7 and <0.8. IgG avidity is a measure of the overall strength of binding of the IgG antibody to the antigen. As time elapses over 3-4 months following primary infection and synthesis of IgG, the bond between IgG and the antigen becomes stronger. Low IgG avidity indicates a recent primary infection. High IgG avidity suggests that the primary infection occurred in the past.

Data Processing and Editing

Data were received after all the antibody testing was complete. The data were not edited.

Data Access: All data are publicly available.

Laboratory Quality Assurance and Monitoring

Commercial reagents were used for all CMV testing. All QC procedures recommended by the manufacturers were followed.

Analytic Notes

There are four variables:

SSCMV: CMV specific IgG results (1=Positive, 2=Negative,
3= Equivocal)

SSCMVOD: CMV IgG Optical Density from the ELISA by Quest International, Inc., Miami FL. Measured in AU/ml which stands for Arbitrary units/ml. Continuous variable - Values range from 0.048 to 3.001. Values reported as “out of range” (i.e. over the detectable range, > 3.00) were assigned values of 3.001.

SSCMIGM: CMV IgM antibody testing results (1=Positive, 2=Negative, 3=Equivocal)

SSCMIGGA: CMV IgG avidity testing results (1=Low, 2=High, 3=Intermediate, 4=Not evaluated)

Subsample Weights

Sample weights are required to analyze these data properly. Specific sample weights for this subsample are included in this data file and should be used when analyzing these data. When observations were removed from this data file, new sample weights were created and  added to this data file (WTSSMC2Y, WTSSMC4Y). Please refer to the NHANES Analytic Guidelines and the on-line NHANES Tutorial for further details on the use of sample weights and other analytic issues.

References

• Dollard SC, SA Staras, MM Amin, DS Schmid, MJ Cannon. National prevalence estimates for cytomegalovirus IgM and IgG avidity and association between high IgM antibody titer and low IgG avidity. Clinical and Vaccine Immunology. 11:1895-1899 (2011).
• Joassin, L., and Reginster, M. “Elimination of nonspecific cytomegalovirus immunoglobulin M activities in the enzyme-linked immunosorbent assay by using anti-human immunoglobulin G”. Journal of Clinical Microbiology. 23:576-581. 1986.
• Peckham, C.S. “Cytomegalovirus in the neonate”. Journal of Antimicrobial Chemotherapy. 23:17-21. 1989.
• Starr, S.E., and Friedman, H.M. “Human Cytomegalovirus”, Chapter 65 in Manual of Clinical Microbiology, fourth edition, edited by E.H. Lennette, A. Balows, W.J. Hausler, Jr., and H.J. Shadomy, American Society for Microbilolgy, pp 711-719. 1985.

Codebook and Frequencies