Blood type testing: Our molecular detectives
As a blood donor, you probably already know your blood type as some combination of A, B, O and then a positive or negative. Apart from these, there are many other blood groups out there (you can read about blood types and why they matter here). Each blood group is a marker on the outside of your red blood cells. In some patients it's important that we match blood transfusions closely to avoid problems.
When your blood arrives at one of our Lifeblood processing centres, some of our team test a sample of your blood while others process your donation. We test the blood type of every donation before we send it to hospitals. That means we do thousands of blood type tests every day!
Behind the scenes, we have a dedicated team of scientists, technicians and high-tech equipment to test your donations accurately and get them to hospitals as quickly as possible.
When you first give blood, we test it using two different methods, so we can be extra sure of the result. “We test your blood type each time you come to give blood or platelets, and we cross check the results with your previous donations to guard against any mix-ups” explains Sue Ismay (Scientific Director, Manufacturing and Quality). Each of these tests takes a tiny drop of blood (to be precise, it’s about 1/250th of a teaspoon, or 20 microlitres).
These tests rely on detector molecules known as antibodies that tag the blood group markers on your red cells. They work well for more than 99% of samples. These tests use sophisticated automated equipment, and we review and manage the results using specialised software. “In recent years, many processes that used to be done by hand have been automated. This increases the quality and consistency of the product, and makes work safer for our staff who are exposed to blood during testing. We’re able to process more samples and ultimately benefit more patients. This speed of testing is especially important for products with short shelf lives, like platelets” says Sue.
The tricky cases
If the automated system produces an unusual result, our specialists in the Red Cell Reference laboratory, led by Tanya Powley, swing into action. They use years of experience to interpret subtle results that may be missed by high-throughput machines. Scientists in this team, along with their collegues in Research and Development, use state of the art genetic testing and a battery of specialised biological tests. Some tests use unlikely materials such as guinea pig urine and pigeon egg white. (Keep your eye on our future blogs for more details).
Because they are often charting new territory, red cell reference scientist's processes aren’t all automated. Each investigation is tailor-made, and although some cases can be solved very quickly, others may take years and a team of international experts to solve. Our red cell reference scientists are molecular detectives, and they never give up!
When a problem is particularly tricky, Tanya and her team collaborate with the Lifeblood Research and Development team and specialists around the world. Just like detectives, our laboratories are pulling out some “cold cases” that we couldn't solve with previous technology. By using new technology on these cases, we now see new blood groups being discovered every year.
“I will retire when I stop having questions to ask” says Tanya “or when I stop having the capacity to ask them”.