LYNN – Students and faculty of St. Mary’s High School in Lynn lined up to give blood Wednesday in a blood drive for The Children’s Hospital in Boston.Forty-five people signed up to donate blood, said Joe Gill, 17, of Lynn. Gil is vice president of the senior class and a volunteer for the blood drive. He is also on the soccer team.”The soccer team can’t donate because they have games,” he said. “But some of the soccer players are going to go into Boston to donate as a team this week on an off day.”The blood drive was for students and staff only; the community was not invited to donate. The school is planning another blood drive in the spring.Dick Ruth of Lynn has donated blood over 100 times. He is a part-time teacher at St. Mary’s and also works part time at Cuffe-McGinn Funeral Home.”Blood supply is always necessary,” he said. “Whether it’s the holidays or a hurricane or accidents or what have you. It’s important. I donate as often as I can.”Louise Sheehan, a 17-year-old senior at St. Mary’s, agrees.”It’s for a good cause,” she said as she winced and turned her head, not wanting to see the needle entering her arm.Brad Brennan, a senior from Peabody, was a little nervous about donating blood for the first time.”I thought it was a good way to give back and help people and the Children’s Hospital,” he said. “(As students), we’re only just old enough to donate, so for a lot of us it’s our first time.”In Massachusetts, donors must be at least 17 years old and weigh 110 pounds; so most high school students are ineligible to donate blood until their senior year.Louise said that all of her friends are also participating.”Everybody wants to donate,” she said.Blood type O-negative is the most useful blood type because any recipient can use this type of blood. People with AB-positive blood can receive any type of blood. Types O-positive and A-positive are the most common blood types in the United States. Unfortunately, people with these blood types donate the least.There are various restrictions on who can donate blood, including medications, travel and health concerns. If you are unsure if you are eligible to donate, any nurse orchestrating a blood drive can answer any questions you might have.If you are interested in donating blood, visit www.givelife.org to find the closest donation center to you. There are upcoming blood drives in the area, including Nahant, Revere, Salem and Danvers.