• Component Description
• Eligible Sample
• Description of Laboratory Methodology
• Data Processing and Editing
• Analytic Notes
• Codebook
  • SEQN - Respondent sequence number
  • WTSSCB2Y - Cardiac biomarkers 2 year weights
  • WTSSCB4Y - Cardiac biomarker 4 yr weights 1999-2002
  • SSBNP - NT-proBNP pg/ml
  • SSBNPL - NT-proBNP comment code
  • SSPRIS - Pristine sample

National Health and Nutrition Examination Survey

1999-2004 Data Documentation, Codebook, and Frequencies

N-terminal Pro-BNP (Surplus) (SSBNP_A)

Data File: SSBNP_A.xpt

First Published: July 2022

Last Revised: NA

Component Description

Sera from stored surplus specimens in the NHANES 1999-2004 cycles were tested for NT-proBNP.

Eligible Sample

NHANES participants aged 1 year or older who consented to storing their samples for future research and had stored samples from 1999-2004.

Description of Laboratory Methodology

This stored specimen study was conducted by the Principal Investigator (PI) Dr. Elizabeth Selvin at the Johns Hopkins Bloomberg School of Public Health. All measurements were performed during 2018-2020 at the University of Maryland School of Medicine, Baltimore, Maryland (Lab Director: Dr. Robert Christenson).

NT-proBNP
NT-proBNP (Roche Diagnostics) was measured in serum on the Roche Cobas e601 autoanalyzer. The lower and upper limits of detection are (5 pg/ml, 35000 pg/ml).

CVs: 3.1% (low, 46 pg/ml) and 2.7% (high, 32805 pg/ml)

The NT-proBNP result is expressed as pg/ml.

Data Processing and Editing

Data were received after all analyses were complete. The data were not edited.
Data Access: All data are publicly available.

Analytic Notes

Refer to the 1999-2000, 2001-2002, and 2003-2004 Laboratory Data Overview for general information on NHANES laboratory data. For information on the stored specimens, refer to the NHANES Biospecimen Program.

Detection Limits
The detection limits were constant. The variable name ending in “L” (ex., SSBNPL) indicates whether the result was either measurable, below the lower limit of detection (LLOD) or above the upper limit of detection (ULOD): A “0” value means that the result was measurable. A “1” indicates that the result was below the LLOD. A “2” indicates that the result was above the ULOD. For analytic results below the limit of detection (ex., SSBNPL=1), an imputed fill value was placed in the analyte results field. This value is the limit of detection divided by square root of 2 (LOD/√2).  For analytic results above the limit of detection (ex., SSBNPL=2), an imputed fill value equal to the value of the ULOD was placed in the analyte results field.

The variable prefixed SS (ex., SSBNP) provides the analytic result.

An indicator variable (SSPRIS) is included for whether the analyte was measured in a pristine sample (never thawed): 0=non-pristine; 1=pristine.

The limits of detection (LODs) for NT-proBNP are:

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 (WTSSCB2Y, WTSSCB4Y). 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. These sample weights are shared with file: “SSCARD_A”, which was from the same sample of survey participants.

The work was funded by a grant (PI: Elizabeth Selvin) received by the Johns Hopkins Bloomberg School of Public Health from the Biomarkers Consortium of the Foundation for the National Institutes of Health (FNIH).

Codebook and Frequencies