Definition
What Complement C3a measures
C3a is another complement anaphylatoxin. Shoemaker-style workups add it when the differential includes Lyme or other complement-activating exposures.
← All biomarkers
Innate immunityCompleteng/mL
Complement C3a
A second complement split product used when Lyme is on the differential
Illustrative sample band · Synthetic
150ng/mL
0Sample target 0–200 ng/mL270
Why it matters
How clinicians usually read it
It has the same frozen-EDTA handling problem as C4a. It is a Complete venous marker, not an Essential Tasso+ assay.
When it reads low
A lower value can mean
A lower C3a is the usual quiet pattern and is read with C4a, not alone.
When it reads high
A higher value can mean
A higher C3a can mark complement activation or the same in-vitro activation that ruins C4a. Confirm handling first.
Questions for a clinician
Bring the number into a real conversation
01
Do we need C3a for a Lyme-pattern question, or is C4a enough?
02
Was this specimen handled like the C4a tube?
03
How should the C3a/C4a pair change the next step?
Educational boundary
Educational information only. Displayed ranges are illustrative sample bands, not a diagnosis, treatment plan, or substitute for the contracted laboratory report and a qualified clinician.
See it as a sample result
The sample dashboard shows an illustrative reading, target band, and trend for Complement C3a.