ANA titer
Positive likelihood ratio*
Likelihood of disease (%)
Primary care setting†
Specialty setting‡
> 1:1280
9.9
17.0
81
1:640
2.2
4.2
49
1:320
1.1
2.1
32
1:160
0.8
1.6
26
1:80
0.8
1.6
26
1:40
0.7
1.4
23
1:20
0.4
0.8
15