When a Patient Asks Why I Treat Babesia Even if the Tests Are Negative, They Often Say:
“But my test was negative—why are we treating Babesia?”
It’s a fair question.
I’ll often explain that Babesia testing isn’t perfect. False negatives are common. And many patients improve when we treat for Babesia—despite negative test results.
So today, let’s break it down—in the form of a clinical dialogue.
💬 A Clinical Dialogue on Treating Babesia with Negative Tests
Cameron: One of my patients had classic Babesia symptoms—night sweats, air hunger, severe fatigue—but her test came back negative. She asked, “Are we sure I have Babesia?”
Colleague: That’s a tough spot. The tests—like PCR and blood smear—are known to miss cases, especially if the parasitemia is low.
Cameron: Exactly. And Babesia can persist in tissues, not just the bloodstream. By the time symptoms show up, the parasite may not be detectable.
Colleague: So you’re relying on clinical diagnosis?
Cameron: Yes. I look at the full picture—especially when a patient isn’t improving with Lyme-only treatment. If they have night sweats, POTS, air hunger, or unexplained drops in oxygen levels, Babesia is high on my list.
Colleague: Have you seen patients get better on Babesia treatment even without positive tests?
Cameron: Many times. Some improve dramatically with atovaquone and azithromycin. Others need more aggressive treatment. The point is—symptoms, not just test results, guide treatment.
🔬 What the Research Shows
- Babesia PCR and smear have limited sensitivity—false negatives are common, especially in chronic cases.
- Studies (e.g., Krause et al.) show Babesia can persist despite negative tests.
- Babesia duncani may not be picked up by B. microti-focused tests.
- Immunocompromised patients often test negative despite active infection.
🩺 Why Clinical Judgment Still Matters
- Tick-borne diseases often co-occur and mask each other.
- Tests are snapshots—symptoms are the full story.
- Negative tests shouldn’t exclude treatment when clinical signs are strong.
- Empiric treatment can be diagnostic and therapeutic.
What I Do in My Practice
- I ask about hallmark Babesia symptoms: night sweats, air hunger, fatigue, autonomic issues.
- I treat empirically when symptoms are consistent and Lyme-only treatment has failed.
- I monitor response closely—improvement can confirm the diagnosis.
- I adjust treatment based on clinical response, not just lab data.
🧭 Final Thoughts
Babesia is often missed—not because it’s rare, but because testing is limited.
When patients present with persistent symptoms and negative tests, I don’t dismiss them—I dig deeper.
If treatment for Lyme disease alone isn’t working, I ask: What if it’s Babesia?
A negative test shouldn’t be the end of the conversation. It should be the start of a closer look.
That’s why I treat Babesia when the symptoms fit—even if the test doesn’t.
I recently have read reports of the babesia strain Odocoilei being far more common that once supposed. I have also been reading recently that this strain might be a “missing link” in patients with refractory TBDs, who when treated for this strain, have shown improvements. Questions: does this strain cause the same symptoms as other babesia strains? And, might it be wise to assume this strain is a culprit, despite lack of symptoms and despite positive testing. To my understanding it is T-Labs that is picking this up. Thank sincerely for for all you do. Mary
You raised questions that have yet to be resolved. We are all waiting for information.
Can immune systems cure Babesiosis. I believe I’ve had TBD (Lyme) for 70 years, but among innumerable symptoms, I had some attributable to babesiosis that came and went. eg drenching night sweats that continued nightly for about 3 weeks then never returned. Also, air hunger that meant I could not sleep in bed for about 5 weeks, then all was OK again.
Should I worry if it was babesiosis? My long delayed treatment for Lyme was not successful.
The immune system does not appear to be very successful at clearing untreated tick borne infection. Some get better with their first treatment. Some of my patients benefit from retreatment. I have had patient who were not treated long enough for Babesia with Zithromax and Malarone.