Can donating blood in New York help those injured in Las Vegas?

Yes. While it’s the local blood on the shelves at the time of a tragedy that actually saves lives, Ms. Corvaia said, New York is a blood exporter. Last year, 151,338 donors in our region gave 273,406 units of red cell donations to the Red Cross, Ms. Corvaia added, the most in the nation compared to other Red Cross regions. With a strong blood supply, the New York region can export blood if the need arises. If you donate blood to the Red Cross, you can even track when and at what hospital it is used, Ms. Corvaia said.

How can I donate?

There are three types of donations. There’s the standard blood donation, where a needle is put your arm and about a pint of blood is extracted. There’s also “power red.” “That’s when we hook you up to a machine and we extract two units of red cells, and then we give you back the plasma and the platelets,” Ms. Corvaia said. The final type is platelets donation, where platelets are kept and red cells are returned to your system.

Is there a blood type that is needed more than others?

Yes. The most useful is O-negative. No matter what type of blood you have, you can receive type O-negative blood. For plasma and platelets, the universal donor blood type is AB.

Is everyone allowed to give blood?

No. You must be in good health, at least 17 years old (or 16 with parental consent), and weigh at least 110 pounds. There are also a number of other restrictions set by the Food and Drug Administration. For example, men who have sex with men must abstain from sex with other men for more than a year before giving blood. Those who received a tattoo in some states, including New York, must also wait 12 months before donating.

How often can I donate?

You can donate every 56 days for standard blood donations. The “power red” donation can be done every 112 days. You can give platelets donations every seven days up to 24 times a year.