| Deficient | Low | Adequate | High |
---|---|---|---|---|
Serum* | Â | Â | Â | Â |
niacin (mg/mL) |  | <0.5 | 0.5 − 8.45 | >8.45 |
Urine †|  |  |  |  |
adults (men; and nongravid and 1st trimester women) | <0.5 | 0.5 − 1.59 | 1.6 − 4.29 | ≥4.3 |
2nd trimester women | <0.6 | 0.6 − 1.99 | 2 − 4.99 | ≥5 |
3rd trimester women | <0.8 | 0.8 − 2.49 | 2.5 − 6.49 | ≥6.5 |
2-pyridone/N1-methylnicotinamide | <0.5 | 0.5 − 0.99 | 1 − 4 | >4 |