Vitamin D tests certified by CDC CSP are well-calibrated but show some inaccuracies, per ENDO 2024 study.
Lead researcher Otoe Sugahara highlighted that blood tests show "appropriate" analytical accuracy.
Sugahara noted inaccuracies are due to lack of analytical specificity and other factors in assays.
Vitamin D is crucial for bone health, making these tests highly requested in the U.S., Sugahara said.
The VDSCP, started in 2013, aims to assess and improve vitamin D test accuracy, per CDC.
VDSCP participants' average calibration bias was under 1% in 2022, showing improved accuracy.
Immunoassays had a 0.86% bias, while mass spectrometry assays showed a 0.55% bias, Sugahara reported.
Despite improvements, sample-specific inaccuracies persist, with CDC working to resolve these issues.