How Convalescent Plasma May Help Fight COVID-19

The American Red Cross has partnered with Creative Testing Solutions to help the nation’s screening efforts for COVID-19 through antibody testing. The Red Cross’ screening efforts enable the distribution of convalescent plasma to ensure patients have access to a lifesaving treatment during this difficult time.

Between June 15 and Oct. 31, the Red Cross tested more than 1.8 million donations in 44 states. Of those donations tested, approximately 2.8% were positive for COVID-19 antibodies. According to Dr. Pampee Young, Chief Medical Officer of the American Red Cross, “With only 2% of the U.S. population testing positive for COVID-19 antibodies, finding eligible convalescent plasma donors to help patients is a little like finding a needle in a haystack.” With this scarcity of eligible donors, The Red Cross is encouraging those who have fully recovered from COVID-19 to roll up their sleeves and donate COVID-19 convalescent plasma!

What is COVID-19 Convalescent Plasma and why is it important?

The blood circulating through the body is made of four main parts: red blood cells, white blood cells, platelets and plasma. When a new virus enters the body, the immune system makes new antibodies to fight the illness. Blood containing antibodies for this virus can sometimes be used in transfusions to help another patient recover from the same illness.

In August, the U.S Food and Drug Administration (FDA) issued an Emergency Use Authorization (EUA) for convalescent plasma as a treatment for COVID-19.  To be eligible to donate convalescent plasma, the donor must have a prior, verified diagnosis of COVID-19, be symptom free, be at least 17 years old and weigh at least 110 lbs. Additional weight requirements apply for donors age 18 or younger.

What is an antibody test and why is it important?

An antibody test screens for antibodies in your blood. Antibodies are formed when fighting infection, like COVID-19. An antibody test assesses whether your immune system has responded to the infection, not if the virus is currently present. Specifically, the COVID-19 antibody test used by the Red Cross is available through Emergency Use Authorization by the U.S. Food and Drug Administration. Test results may indicate if the donor’s immune system has produced antibodies to the coronavirus, regardless of whether they developed symptoms.

Potential limitations of antibody testing are recognized at this time in the pandemic and the Red Cross has added secondary testing of all donations that come back positive to confirm COVID-19 antibody test results for donors. In addition, the COVID-19 antibody test used by the Red Cross measures total antibodies, unlike some tests that measure a single class of antibodies.

Currently, medical experts do not know how long COVID-19 antibodies are detectable in blood after recovering from COVID-19 illness. However, based on previous data during other coronavirus outbreaks, such as SARS, antibodies remain detectable in blood for several months, but levels start to decline soon after infection clears. Antibody loss may be quicker in persons with mild illness or who have had no symptoms

Testing all blood donations for COVID-19 antibodies will be helpful for the collection of much-needed convalescent plasma products. As part of this effort, plasma from whole blood donations that test positive for COVID-19 antibodies – using two different antibody tests – may now help current coronavirus patients in need of convalescent plasma transfusions.

Red Cross antibody tests will also be helpful to identify individuals who have COVID-19 antibodies and may qualify to be convalescent plasma donors for future donations.

Donations will be tested using samples obtained at the time of donation and sent to a testing laboratory where the samples will also undergo routine screening and infectious disease testing. The test may indicate if the donor’s immune system has produced antibodies to this coronavirus, regardless of whether an individual experienced COVID-19 symptoms.

After a donation of blood or platelets, donors can log into the Blood Donor App to view a record of their vitals taken during pre-donation screening as well as the results of the antibody test. The following are the different types of results:  

• Positive: A positive test results indicates potential previous exposure to the virus that causes COVID-19 resulting in the development of specific antibodies to the virus, regardless of whether an individual experienced COVID-19 symptoms. It does not confirm infection or immunity and donors should continue to follow all COVID-19 safety guidelines provided by the CDC. It is unknown if the antibodies that result from a COVID-19 infection will provide someone with immunity from a future coronavirus infection.
• Negative: A negative result most likely means that the individual has not been exposed to COVID-19 and therefore has not developed antibodies to the virus. It also could mean that antibodies are present but at levels below the test’s threshold for detection, or that the test did not recognize those antibodies that a donor made.
• Pending: A pending test result means that the test is still in process. Red Cross donors can expect to receive the results of their antibody test within one to two weeks through our Red Cross Blood Donor App or on our donor portal at RedCrossBlood.org.
• Inconsistent: An inconsistent test result means that the Red Cross found differing test results for COVID-19 antibodies after secondary testing. For example, a donation test result was initially positive for COVID-19 antibodies, while secondary testing results came back negative for COVID-19 antibodies. As with all tests, false positives, or a test result that incorrectly states the presence of antibodies, can occur. Alternatively, the level of COVID-19 antibodies may be too low to detect by the second test. The Red Cross may contact the donor to request additional information and may test the sample for additional test results.
• Not available: While rare, some donations may not be able to be tested due to processing issues. Donors will need to have a successful donation to receive COVID-19 antibody results. Per standard procedures, only successful donations are sent to our laboratory for testing.

The same information can be obtained in the donor portal at RedCrossBlood.org. Results will be posted within one to two weeks after the donation is completed. Those who receive a positive antibody test result may be eligible to participate in the convalescent plasma donation program. Visit the Coronavirus Convalescent Plasma Donation page for more information about the program and donor eligibility.

It’s important to note that the body typically takes one to three weeks after initial infection to develop antibodies, and there is some evidence that antibodies decrease over time. Therefore, having a negative antibody test does not necessarily indicate that an individual has never had contact with COVID-19. The antibody test is not a diagnosis for COVID-19. As mentioned before, the antibody test only determines the presence of antibodies that fight against COVID-19 in the blood. At this time, it is currently unknown whether the presence of COVID-19 antibodies will provide immunity to future infection.

A test used to diagnose COVID-19 is known as a diagnostic test. Diagnostic tests are completed by a health care provider looking for evidence of the virus in the body at a specific point in time. Furthermore, it is important that individuals who do not feel well or believe they may be ill with COVID-19 postpone any donations.

The Red Cross is committed to keeping you safe during donation.

Each blood drive or donation center follows the highest standards of safety and infection control. No one is permitted to enter a blood drive or donation center without an approved mask or face covering. All blood donations are tested for multiple infectious diseases before being released for clinical practice. To further ensure the health and safety of our community, staff and donors must undergo temperature checks before they are permitted to participate in a drive. The Red Cross also provides hand sanitizer for everyone present.

All staff use a clean set of gloves, an aseptic scrub and sterile collection sets for every donation. After donation, the staff disinfect surfaces, equipment and donor-touched areas. Additionally, the Red Cross enforces social distancing at the collection site.