National Health and Nutrition Examination Survey

2001-2002 Data Documentation, Codebook, and Frequencies

Human epididymal secretory protein E4 (HE4) - Serum (Surplus) (SSHE4_B)

Data File: SSHE4_B.xpt

First Published: May 2020

Last Revised: August 2022

Note: The NHANES Biospecimen Program processes were reevaluated in 2021 and 2022 to monitor quality control after a procedural error was identified. This error did not pose any risk of participant disclosure. Addressing this error resulted in the removal of some records from various stored biospecimen data files between 1999 and 2018 that did not meet program standards. After a comprehensive review of all stored specimen datasets, this data file was modified to remove records (5-<10% of records) that were initially included in error. No data values were altered. The sample weights and overall estimates were compared between the original and revised files. The sample weights provided with the original data release are appropriate to use with this updated data file; therefore, no new survey weights were created. The overall estimates from these files were examined and are consistent with the previous file. However, not all possible analyses were performed.

Component Description

Sera from residual specimens from NHANES 2001-2002 participants were tested for levels of human epididymal secretory protein E4 (HE4). The results for HE4 in this data release are reported as pM.

Eligible Sample

Female participants age 20+ who consented to storing their samples for future research and had stored samples from 2001-2002.

Description of Laboratory Methodology

All measurements were performed in the Genital Tract Biology Laboratory (Brigham and Women’s Hospital, Lab Director Fichorova) following pre-analytic, analytic, and post-analytic standardized operational procedures (SOPs) established under the Laboratory Director and special chemistry accreditation by the College of American Pathologists. The lab used the Meso Scale Discovery (MSD) (Gaithersburg, MD) electrochemiluminescence immunoassay platform. Quality control (QC) pools were prepared and split into multiple aliquots. To establish inter-and intra-plate variability, one aliquot of this pool was repeatedly tested on each assay plate. A coefficient of variation of < 25% was set as a threshold for acceptance of the data.

In further detail, the following assays and methodology were applied:

Human Prototype HE4 (96-well prototype plate 4 spot, catalog number N45YA-1)

The linearity range for the HE4 was 3600–0.55 pM (lowest limit of detection (LLD) 0.006 pM). All samples were tested undiluted and 47 samples were repeatedly tested to verify values <1 and >99 percentile. One plate was repeated due to systematically lower/outlier values. Three QC samples were used spanning three logs of the assay range: 1) a plasma pool prepared by pooling a small volume (5 ul/ sample) from over 2000 serum samples which had shown measurable HE4 levels in a prior study using the MSD platform^1,2; 2) a QC generated from a standard of known HE4 concentration; 3) a plasma pool prepared by pooling samples obtained from a cohort of ovarian cancer cases.

The unblinded quality control sample pool repeatedly tested on every assay plate showed the following inter-plate CV and min–max range (mean) of intraplate CV of the three QCs tested: (i) QC #1, 18.3% inter-plate CV and 0.2%–9.2% (2.9%) intraplate CV; (ii) QC #2: 21.25% inter-plate CV and 0.2%–14.4% (3.3%) intraplate CV; and iii) QC #3: 15.04% inter-plate CV and 0.3%–12.3% (3.1%) intraplate CV.

Laboratory Quality Assurance and Monitoring

The acceptable QC pool variation was set to 25%. Back fit analysis of each calibrator was also set to 25% acceptable level. Outliers were confirmed by repeated testing and samples outside the linearity range of each assay were repeatedly tested at adjusted dilution to produce acceptable value.

Data Processing and Editing

Data was compiled into a database after all the assays were completed and passed quality control criteria. The data were not edited.

Data Access: All data will be made publicly available.

Analytic Notes

Results were measured as pM.

Exam sample weights should be used for analyses. 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.

Code or Value	Value Description	Count	Cumulative	Skip to Item
0.38 to 466.9	Range of Values	2388	2388
.	Missing	0	2388

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