From: Influence of sample collection tube method, anticoagulant-containing plasma versus serum, on influenza virus hemagglutination inhibition titer and microneutralization titer serological assays
SST Titer
Type A, H1N1
Type B
< 40
2
1
40 - < 80
3
80 - < 160
5
160 - < 320
7
6
320 - < 640
9
640 - < 1280
4
1280