The richest ZIP code in the US, a private island off the coast of Miami, has spent $30,600 on coronavirus antibody tests for all of its residents and staff, The Miami Herald first reported.

Fisher Island bought 1,800 tests that cost $17 each from the University of Miami Health System, for a total of $30,600, The New York Times reported. The finger-prick blood tests deliver results in about 10 minutes.

"This is what the Fisher Island residents wanted," UHealth spokeswoman Lisa Worley told the Herald.

The 800 families who live on the members-only island, who have an average income of $2.2 million, pay $22,256 in annual dues to live there — and that's on top of an initial $250,000 fee and buying a multimillion-dollar condo. Annual dues include the payer's spouse and children up to the age of 24. Homes in the island's nearly 30 luxury condominium buildings start at $2 million and can cost upwards of $40 million.

Half of Fisher Island residents are over age 60 and at high risk, Sissy DeMaria Koehne, a spokesperson for the island, said in a statement to Business Insider. Testing started on April 6, with 1,250 people tested so far, according to the Times. The island's 400 staff members will also be tested.

About 800 families live in 30 luxury condominium buildings on Fisher Island. Katie Warren/Business Insider

Elena Bluntzer, a real-estate agent who lives on Fisher Island, told Business Insider on Tuesday that she'd already gotten tested at the island's clinic.

"It's just a finger prick," she said. "You go and make an appointment along with everybody else and it's set up in such a way that there is a lot of social distancing." The fingerprick blood test determines if someone has been exposed to COVID-19 and has developed antibodies to the infection.

"It's extremely well set up," Bluntzer said, adding that no one she knew of had had a test come back positive.

The tests bought by Fisher Island are not yet available to the wider public, according to the Herald.

Fisher Island plans to test residents "building by building," according to an April 7 letter to residents viewed by Business Insider and signed by Dr. Elizabeth Greig, the medical director of UHealth Fisher Island. According to the letter, every resident will receive a date on which they would be required to be "on call" for participating in testing, as Business Insider's Taylor Borden reported. The letter notes that the test is voluntary.

The island has between five and nine confirmed coronavirus cases, according to Florida's Department of Health coronavirus cases map. There are more than 7,800 cases in Miami-Dade County and upwards of 22,000 cases in the state of Florida.

Fisher Island, which is only accessible by ferry or private boat, has closed most of its amenities, which include a beach club, multiple restaurants, a golf course, two deep-water marinas, a spa, and 18 tennis courts. Even the beaches, where the pristinely white sand is imported from the Bahamas, are currently off-limits.