ISSAQUAH, Wash. — Costco Wholesale Corp. is testing prescription drug delivery via Instacart in California and ­Washington.

Costco pharmacy customers and Instacart members over the age of 18 can get medicines delivered within an hour, with fees waived on orders of $35 or more. Fees on orders that don’t reach the cart minimum depend on how quickly the shopper needs the medication but usually add less than $10 to the transaction cost.

News of the pilot was first reported by CNBC, which cited a Costco member who had received text notification from the company offering the delivery option as an alternative to a store visit.

CNBC reported that Instacart delivery personnel will ask for proof of identity to ensure they’re delivering the medications to the right person, and the checkout process requires buyers to confirm their date of birth. There is also an option for a phone consultation from a Costco pharmacist.

Instacart workers will be allowed to deliver medications only if they pass a HIPAA certification training, meaning they’re aware of the rules around managing people’s sensitive health ­information.

Costco recently expanded its partnership with San Francisco-based Instacart to include all of its more than 500 warehouses as a way to build convenience and loyalty among its affluent shopper base. Prescription delivery is expected to further deepen those ties.

For Costco, the pilot also represents an opportunity to remain competitive with the pharmacy delivery programs of rivals such as CVS Pharmacy, Walgreens, Amazon and Walmart.

In terms of logistical capabilities, each of these retailers is playing catch-up with NowRx, an on-demand pharmacy based in Silicon Valley and founded in 2017 with the goal of developing software, artificial intelligence, robotics and logistics to create the most convenient retail pharmacy service available, focused on free same-day delivery for prescription and over-the-counter medications. NowRx employs a team of pharmacists who use the firm’s proprietary pharma-efficiency technology to fill prescriptions at its locally based and fully licensed pharmacies. The drugs are hand-delivered on the same day though its fleet of drivers.