Massachusetts is in the midst of a blood shortage due to a decline in blood donations, a spokeswoman for the American Red Cross said Monday. Meanwhile, officials at Martha’s Vineyard Hospital said demand for blood on the Vineyard has increased with the summer swell in population.

Those involved with blood supply agree the current situation makes a high turnout critical for this Thursday’s Martha’s Vineyard Community Blood Drive.

Those looking to help out can call 1-800-448-3543 to schedule a time to donate blood between 12 noon and 6 p.m. Thursday at the Portuguese-American Club on Vineyard avenue in Oak Bluffs.

“Right now we have an urgent need for blood,” said Melissa Quinlan, a spokeswoman for the American Red Cross in Massachusetts. “With all blood types, we have about a day’s supply of blood.”

Ms. Quinlan said Red Cross usually likes to keep a three to five-day supply, but that the summer season, as it does every year, has led to a decrease in blood donations. The organization heavily depends on student donations at high schools and colleges, which have let out for the summer months. Also, people are away on vacation and are less concerned with donating blood.

“If people who were out vacationing would pencil in a bit of time to donate blood, that would be amazing,” she said.

The Vineyard suffers the opposite problem from the rest of Massachusetts. Supplies are low in the summer, not because of a decrease in donation, but because of an increase in population, which leads to an increased demand for blood.

“We have a very low supply of blood and blood products on the Island,” said Dr. Timothy Tsai, director of emergency medicine at Martha’s Vineyard Hospital. “The need increases in the summer because the population expands.”

More people mean more accidents and more patients in need of blood.

Because of the low levels of blood, Lynn Mercer, the lab manager at the hospital, which oversees the Island’s blood bank, called donor drives like the one on Thursday critical.

“We’re just meeting our demand,” she said. “You can’t overstate the need to get people out and donate.”

Officials agree that the blood type in the greatest need is O positive, which can be given to almost anyone of any blood type. But, they maintain, it is important for everyone, of every blood type, to donate. The goal of the drive is to collect 80 usable units of whole blood donations.

As if the looming possibility of the state running out of blood isn’t enough to get people out on Thursday, the American Red Cross has also thrown in the added incentive of coupons for free chocolate and the chance to win Red Sox tickets as Blood Donor of the Game.

According to a press release from the Red Cross, people 17 years of age or older, weighing 110 or more pounds and feeling in good health may be eligible to donate. The process will take about an hour.

The American Red Cross, which controls 43 per cent of the nation’s blood supply, came under fire last week when a New York Times article detailed the organization’s problems complying with the Food and Drug Administration’s rules and procedures.

In response, the American Red Cross released a prepared statement saying, “The highest priority of the American Red Cross is the safety of our donors and the recipients of blood.”

The statement went on to say, “The FDA agrees the blood supply is safer than it has ever been, and we strongly encourage the public to continue to give and receive blood so lives can be saved.”