National Health and Nutrition Examination Survey

Lab Public-Use Data Files Usage Notes

File Location LAB
Section Hepatitis B surface antibody (SSP)
Date August, 2002

Hepatitis B surface antibody testing was only done on hepatitis B core antibody positives. In 1993, 495 additional samples from participants with a medical occupation who were negative for antibody to hepatitis core antigen were tested to determine mIU/ml of antibody to assess vaccination status. Results of the serum hepatitis B surface antibody can not be used to estimate the vaccination status of the U.S. population since all participants were not tested for this serologic marker.

File Location LAB
Section Serum Biochemistry Profile - All analytes in Biochemistry Profile
Date September, 2002

Additional note to explain possible storage effect on analytes in biochemistry profile

Sera for the Biochemistry Profile was stored at –20° C and then thawed at room temperature. This freeze/thaw cycle has been demonstrated to result in degradation for some analytes in this profile (1-2). Analytes should therefore be used cautiously since degradation could have occurred.

  1. Mosley JW, Goodwin RF. Stability of serum-glutamic pyruvic transaminase activity on storage. Tech Bull Regist Med Technol 1965;35:183-187.
  2. Young, D.S.,ed., Effects of Preanalytical Variables on Clinical Laboratory Tests, 2nd Edition. AACC Press, Washington DC, 1997.