Monitoring Accuracy – AMP Vitamin D

Key points

The measurement accuracy of laboratory tests used routinely in patient care, research, and public health studies can change over time. It is important to note these changes so that correct measurement results are reported. CDC monitors the accuracy of measurements performed in routine laboratories over time for Total 25-hydroxyvitamin D.

Test tubes in laboratory

Monitoring accuracy

CDC offers a formal program for laboratories to monitor their tests, and another program for researchers to monitor contract laboratories.

CDC monitoring programs

CDC CSP enables laboratories and investigators to continuously monitor the accuracy of measurements in patient care and research studies over time.

Program

Analytes

CDC Lipid Standardization Programs (LSP)

Total Cholesterol, Total Glycerides, HDL-Cholesterol, Apolipoprotein AI, Apolipoprotein B

CDC Accuracy-based Monitoring Programs (AMP)

Total 25-hydroxyvitamin D, Total Testosterone

CDC Accuracy-based Blind Quality Control Program

Total Testosterone, Estradiol, Total Cholesterol, Total Glycerides, HDL-Cholesterol, Free Thyroxine, Total 25-hydroxyvitamin D

CDC Accuracy-Based Monitoring Program (AMP) for Vitamin D

Using the following process, CDC's Accuracy-Based Monitoring Program (AMP) helps laboratories monitor the accuracy of their own vitamin D tests over time:

  1. CDC provides participants samples with reference values unknown to the participant.
  2. Participants measure these samples weekly along with their regular patient or study samples.
  3. Participants report the results of their sample measurements to CDC.
  4. Using established statistical assessment procedures, CDC compares participants' results to the actual concentrations determined with the CDC reference measurement procedures.
  5. CDC provides participants with quarterly assessment reports.

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CDC AMP - Vitamin D Participant Protocol

CDC Accuracy-Based Monitoring Program Participant Protocol

CDC Accuracy-Based Monitoring Program Participant Protocol

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List of participants within performance criteria

Scientists in Laboratory

Vitamin D Certified Assays and Participants

List of Vitamin D Certified Assays

Accuracy-based blinded quality control program

Using the process below, CDC's laboratory assessment programs help researchers monitor the accuracy of their contract laboratories' tests:

  1. CDC provides researchers with "blinded" quality control samples, meaning the quality control samples cannot be differentiated from the study samples. These are vials with serum samples an investigator adds to batches of vials with study samples. These vials are labeled in the same manner as regular study samples. The number of quality control samples used, and the frequency with which they are added to the study samples, can vary depending on the needs and requirements defined by the investigator.
  2. The laboratory measures the samples and reports the results to the investigator.
  3. The investigator compares the reported values with the actual concentrations using CDC's reference method.

To request blinded quality control samples, contact Standardization@cdc.gov.

Contact the program

To enroll in the AMP - Vitamin D program, contact Standardization@cdc.gov.

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Content Source:
National Center for Environmental Health; Division of Laboratory Sciences