No new coronavirus cases were reported on the Vineyard Friday, leaving the number of positive test results at 24 on the Island.

In their daily update, the Martha’s Vineyard Hospital reported that 548 patients had been tested for the virus, with 23 positives, 516 negatives and nine tests pending. The 24th positive test occurred off-Island and was reported separately by the Island boards of health on Thursday.

On Friday, Tisbury health agent Maura Valley confirmed that the new positive test was actually a positive serology — or antibody — test that occurred at a facility off-Island. The positive serology test marked the first person on the Vineyard to test positive for coronavirus antibodies.

The coronavirus serology test is not available anywhere on-Island, Ms. Valley said.

Even though the patient, a woman in her 50s, never received a positive test, Ms. Valley said that because a positive antibody test indicates the patient had the virus, they would be included in the Island’s total positive case count.

“This is the first time this has happened,” Ms. Valley said. “I had this conversation with our public health nurse yesterday about whether they should be included as positive, and I was told yes, because they were positive.”

Ms. Valley said the boards of health were aware of the patient and had conducted the normal contact tracing procedure when the patient was symptomatic, despite her never receiving a positive test. Ms. Valley said that the patient was no longer showing symptoms, and that the case had been “completed.”

“To be clear, this was a person that was on our radar, that we dealt with when they were sick. And she did do self-isolation,” Ms. Valley said. “We were notified that she was symptomatic but was not tested because it was back when they [Martha’s Vineyard Hospital] were only testing people that were extremely ill. So we followed up and did contact tracing at this time.”

This week, the hospital announced that it had liberalized its testing criteria, allowing almost all symptomatic patients to receive tests. In the past, hospital officials said that they had turned some low-risk symptomatic patients away from tests and told them to quarantine instead.

The hospital reported on Friday that no one had been hospitalized with the virus.

Statewide, the department of public health reported similar numbers as Wednesday and Thursday, with 1,612 patients testing positive for the virus and 150 more deaths. The state now has over 75,000 people who have tested positive for Covid-19, and 4,702 people who have died.

The rate of tests coming back positive has decreased throughout the state in the past week, however, prompting Governor Baker to remark in his press briefing Friday that signs were pointing in the right direction. Statewide, the rate of positive tests is approximately 16 per cent. That number is much lower on the Vineyard, where approximately four per cent of tests are coming back positive.

“We’re making progress here,” the governor said.

A statewide stay-at-home order is in effect until May 18, with a stricter version in place on the Island — although towns took steps this week to further relax construction moratoriums, allowing one-and-two man crews and housecleaners to get back to work. On Monday, some towns will vote on rules that will allow five-men crews to get back to work.

Friday also marked the third day of Gov. Baker’s rule forcing anyone who cannot socially distance in public to wear a mask, which came on the heels of a similar regulation by many towns and transportation agencies on the Island.