Vitamin D testing
As part of our national health professionals program, NPS uses a range of evidence-based strategies to provide unbiased information and promote optimal clinical practice. One of these strategies is self reflection, where GPs are provided with their own current practice data (provided by Medicare Australia and not shared with NPS on an individual prescriber level) together with independent, evidence-based information on national and international practice recommendations.

NPS has provided independent information and evidence-based services to GPs on medicines use for more than 10 years and as a natural progression, has recently expanded this information service to include tests used in diagnosing and monitoring conditions affected by medicines.

The difference between vitamin D testing and supplementation
There is clear evidence of the benefits of vitamin D in our bodies for numerous important functions. Some people are clearly at high risk of disease from vitamin D deficiency and should be treated with a supplement. Vitamin D supplements are available over the counter from pharmacies without a prescription.

NPS has recently made a range of resources on vitamin D available to GPs and the community, including a brochure on vitamin D and pregnancy (available in eight community languages) and a leaflet on vitamin D supplementation. These resources are freely available for GPs to order to provide to their patients.

Currently in Australia, vitamin D tests are only funded by Medicare for use in diagnosis and not for screening. Importantly, there is variability in the tests used for detecting deficiency, the levels of vitamin D reported by different test methods, and advice about what to do at each level. For high risk groups testing has an important role. For some, the result of a test would not actually change the recommendations to use a supplement or safe sun exposure.

In April 2011, NPS published the NPS News 72 with information designed to reduce confusion reported by GPs about testing (see http://www.nps.org.au/health_professionals/publications/nps_news/current/vitaminD)

Vitamin D testing information for GPs
In April 2011, personalised letters were also sent to 18,500 GPs in which MBS data was combined (by an independent mailing house) with information about appropriate vitamin D testing. The letter contained data about the number of vitamin D tests performed in different parts of Australia, as well as GP-specific data about the number of vitamin D tests ordered over the past four years. The information included in this letter supplemented other NPS publications on appropriate vitamin D testing. For example, the self reflection asked doctors to consider their ordering patterns with respect to summer and winter variation (as this affects test results).

A decision about appropriate use of medicines and tests requires clinical judgment in the context of individual circumstances. NPS does not have access to such information and does not make judgments about the appropriateness of individual practice.