Financial impact of California's new law to increase HIV screening by mandating insurance coverage.

To increase HIV testing, in 2008 California's governor signed the first piece of legislation in the USA to require private health plans to cover the cost of HIV testing regardless of whether testing is related to a primary diagnosis. This study assesses the impacts of the bill on coverage, testing rate, and cost for 22,190,000 Californians. All targeted individuals had some form of coverage for HIV testing before the mandate. If minimum expansion of coverage occurs, overall expenditures on HIV testing are projected to increase by US$554,000 in the year following the adoption of the law. If testing broadens to comply with the Centers for Disease Control and Prevention (CDC) testing guidelines, annual expenditures are projected to increase by US$10,151,000. This policy change could serve as a step toward making HIV testing a routine screening test. However, the impact of this mandate largely depends on people's awareness and willingness to adopt the CDC guidelines.