| Value | Category |
|---|---|
| 1 | Blood taken - and valid result obtained |
| 2 | Not present |
| 3 | Refused |
| 4 | Originally 'Blood taken', but no barcode in questionnaire |
| 5 | Originally 'Blood taken', but no corresponding barcode at lab |
| 6 | Other |
| 8 | Nagaland: information not collected |