Roughly one in ten healthy adults has a positive antinuclear antibody at 1:80, and the proportion rises with age. Sent without a clinical question behind it, the test generates more referrals than diagnoses, and a low-titre positive in someone with fatigue and aching is far likelier to be noise than lupus.
Use the titre and the pattern. A titre of 1:80 in an asymptomatic person means very little; 1:640 or more, or a centromere or nucleolar pattern, deserves attention even when the history is thin. A negative ANA on a modern immunofluorescence assay makes systemic lupus erythematosus very unlikely, which is the test's real strength — it is far better at excluding than confirming.
What changes management is what comes next, and only if the ANA is meaningfully positive: extractable nuclear antigens, double-stranded DNA, complement C3 and C4, urinalysis for protein and casts, and a full blood count. Order those because the history points there, not reflexively. And tell the patient before you send the ANA what a positive result will and will not mean, because the number will follow them.
- Ask what you would do with a positive result before sending the test
- Titre and pattern matter: 1:80 is common in health, 1:640 or a nucleolar pattern is not
- A negative ANA makes SLE very unlikely — use the test to exclude, not to confirm
- Follow a meaningful positive with ENA, dsDNA, C3/C4, urinalysis and full blood count
- Never start treatment on a serological result alone, and never label a patient from one
Read the rest in the app
You have read your two free briefings this month. The app carries all 27 specialties, every morning, free — and this finding is waiting in it.
Scan to keep reading on your phone. No account needed to start.
Tomorrow morning, before your first patient
One edition a day for rheumatology, written by the desk, every claim tied to its paper. Six minutes.
Get the app — free