What Diseases Do Blood Banks Test For? Including Babesia Screening
Blood banks test for multiple infections.
Babesia is now included in many screening panels.
Testing can detect infections missed in routine care.
What diseases do blood banks test for?
Blood banks routinely screen for infections such as HIV, hepatitis B and C, West Nile virus, syphilis—and in many U.S. regions, Babesia.
Babesia screening is important because the infection can be transmitted through blood transfusion—even when donors feel well.
Lyme disease itself is not routinely screened in blood donation, but co-infections like Babesia are.
What Diseases Do Blood Banks Test For?
Blood banks screen donated blood to reduce the risk of transmitting infections to recipients.
These typically include:
- HIV
- Hepatitis B
- Hepatitis C
- West Nile virus
- Syphilis
- Babesia (in many U.S. regions)
Babesia was added to screening panels because it can be transmitted through blood and may go undetected in routine medical care.
How Blood Bank Screening Detected Babesia
A routine blood donation revealed a Babesia infection that had been missed for months.
A patient donated blood after experiencing subtle, unexplained symptoms. A week later, he received a letter: his donation had tested positive for Babesia.
The blood bank identified an infection that had not been diagnosed during clinical care.
This illustrates how blood donation screening can uncover infections that might otherwise remain unrecognized.
Why Babesia Is Often Missed
Babesia symptoms can be mild, intermittent, or mistaken for other conditions.
Early symptoms may include:
- Fatigue
- Dizziness
- Shortness of breath
- Night sweats
- Mood or cognitive changes
Many patients do not recall a tick bite.
Because symptoms overlap with Lyme disease symptoms, diagnosis may be delayed.
Babesia Blood Screening: How It Works
Blood banks use nucleic acid testing (NAT) to detect Babesia DNA.
Blood bank screening is often more sensitive than routine clinical testing for Babesia.
This method can detect infection even when symptoms are mild or absent.
This is why blood donation screening sometimes identifies infections before physicians do.
Can Babesia Be Transmitted Through Blood?
Yes. Babesia can be transmitted through blood transfusion.
This risk led to widespread screening in blood donation centers.
Recipients who are older or immunocompromised are at higher risk of severe disease.
What Happens If Your Blood Tests Positive?
If your blood donation tests positive for Babesia:
- The blood is discarded
- You are notified by the blood bank
- You are deferred from future donations
- You should follow up with a physician
This result may lead to diagnosis and treatment of a previously unrecognized infection.
Learn more: Babesia treatment options
Clinical Takeaway
Blood bank screening has revealed that Babesia infections are more common—and more easily missed—than previously recognized.
Because symptoms can be subtle and testing is not always performed in routine care, infections may go undiagnosed without screening.
In some cases, blood donation screening provides the first—and only—clear diagnosis of Babesia infection.
Dr. Daniel Cameron, MD, MPH
Lyme disease clinician with over 30 years of experience and past president of ILADS.
Symptoms • Testing • Coinfections • Recovery • Pediatric • Prevention
