What’s Improved?

Clinical tests used in patient care that are standardized by CDC Clinical Standardization Programs (CSPs) show higher accuracy than tests that are nonstandardized. With tests that are standardized, health professionals can make evidence-based clinical decisions more easily.

Data from proficiency testing programs have shown that CDC-standardized laboratory tests used in patient care are more accurate than nonstandardized tests. For example, the Endocrine Society uses blood testosterone levels to guide clinical decision-making. Those measures, established with the help of our standardized tests, can be used with confidence to correctly assess patients.

Tests that are standardized by CDC CSPs also support the correct assessment of trends in population health.

Many public health activities aim to reduce high cholesterol levels. The National Health and Nutrition Examination Survey provides representative data about the prevalence of high cholesterol in the U.S. population, and can be used to tell whether activities to reduce cholesterol are effective. CDC CSPs have been standardizing blood lipid tests used in the survey for many years. This helps public health officials detect population trends in cardiovascular risk with confidence.

The annual benefit attributable to the CDC Lipids Standardization Program alone is approximately $338 million, at a program cost of $1.7 million, according to a study in Preventing Chronic Disease. The researchers calculated the benefit by estimating the value of reductions in heart disease deaths resulting from various treatments dependent on lipids testing. The study built in conservative assumptions of 0.5% of cholesterol-related benefits attributable to the programs and a $50,000 value per life-year.

CDC CSPs ensured that vitamin D measurements in the VITamin D and OmegA-3 TriaL (VITAL) study were accurate. Findings from this landmark study provided valuable information about the health effects of taking vitamin D supplements on diseases such as cancer.

CDC CSPs ensured that testosterone measurements in the Testosterone Trials study were accurate and reliable. The findings from this study helped scientists prepare clinical practice guidelines.

CDC CSPs continuously monitor the analytical performance of program participants to enable timely corrective actions and avoid problematic changes in performance. As an example, data from CDC’s Lipids Standardization Program helped identify a problem with accuracy of cholesterol measurements from a major test manufacturer. We provided technical assistance to the manufacturer to improve the accuracy and reliability of its measurements, which account for nearly 25% of the cholesterol tests conducted in the United States. This early detection and intervention helped prevent misdiagnosis and misinterpretation of results for an important health indicator.

CDC CSPs provide critical information about reference materials and methods to help with calibration. We apply unique procedures and protocols to characterize reference materials to generate critical data that manufacturers and researchers need to correctly calibrate tests. This substantially reduces any variability in test results.

CDC CSPs collaborate with academic researchers around the world. Successful projects include:

• The development of better pediatric reference intervals or “normal ranges.” As a first step, CDC CSPs collaborated with the American Association of Clinical Chemistry to conduct a thorough review of existing reference intervals and develop a strategy to address their limitations. Findings are published in JAMA Pediatrics.
• Collaboration with the Partnership for the Accurate Testing of Hormones (PATH) to establish reference intervals for testosterone in men that were recommended by an Endocrine Society Clinical Practice Guideline and are now used in clinical practice.
• Collaboration with the National Polycystic Ovary Syndrome Association to standardize testosterone testing for women and children to improve diagnoses of increasingly prevalent endocrine disorders in women, such as polycystic ovary syndrome and certain cancers.
• Collaboration with PATH to define reference intervals for estradiol in postmenopausal women that will improve diagnosis of cancer and treatment of menopausal symptoms.
• Investigation of the impact of lipoprotein(a) variants on measurement accuracy of tests used in patient care. Information obtained from this research helps to assess cardiovascular disease risk more reliably.
• Collaboration with the National Cancer Institute to measure blood levels of different hormones in women with certain cancers. This research will improve identification of women at risk for cancer.

We assist national and international organizations with establishing reference laboratories using the CDC CSPs reference methods. Some of these organizations include:

• Cholesterol Reference Method Laboratory Network (CRMLN)
• International Federation of Clinical Chemistry (IFCC)
• Joint Committee for Traceability in Laboratory Medicine (JCTLM)
• American Association for Clinical Chemistry (AACC)
• Korea Disease Control and Prevention Agency (KDCA)
• Philippines Association of Medical Technologists (PAMET)
• Sociedad Boliviana de Bioquimica Clinica (SOBOBIOCLI)

In addition, we assist other agencies with reference material development and characterization to ensure global availability of critical reference materials. These include organizations such as:

• National Institute of Standards and Technology (NIST)
• National Institute of Biological Standards and Control (NIBSC)
• World Health Organization (WHO)
• Laboratoire national de métrologie et d’essais (LNE)
• European Commission – Joint Research Centre (EC- JRC)