Key Concepts About Identifying Laboratory Methods and CVs and their File Locations

General and specific laboratory information is available for each survey cycle. The method used to measure any given analyte, or the precision of a method may change over time. As a result, data users will find it important to review the information on these laboratory characteristics. The Laboratory Procedure manuals on the NHANES website provide the laboratory method and CV for each environmental chemical measured, as well as details on the laboratory performance, including:

• Clinical Relevance and Summary of Test Principle;
• Safety Precautions;
• Computerization: Data-System Management;
• Procedures for Collecting, Storing, and Handling Specimens; Criteria for Specimen Rejection;
• Procedures for Microscopic Examinations; Criteria for Rejecting Inadequately Prepared Slides;
• Preparation of Reagents, Calibration (Standards), Controls, and All Other Materials; Equipment and Instrumentation;
• Calibration and Calibration-Verification Procedures;
• Operating Procedures; Calculations; Interpretation of Results;
• Reportable Range of Results;
• Quality Control (QC) Procedures;
• Remedial Action if Calibration or QC Systems Fail to Meet Acceptable Criteria;
• Limitations of Method; Interfering Substances and Conditions;
• Reference Ranges (Normal Values);
• Critical-Call Results (“Panic” Values);
• Specimen Storage and Handling During Testing;
• Alternate Methods for Performing Test and Storing Specimens if Test System Fails;
• Test-Result Reporting System; Protocol for Reporting Critical Calls (if Applicable);
• Transfer or Referral of Specimens; Procedures for Specimen Accountability and Tracking;
• Summary Statistics and QC Graphs; and
• References.

 

When analyzing environmental chemical data, review the laboratory methods and CVs for each survey cycle to be analyzed.