| Group | uU/mL or mU/L |
| Premature Infants / Children | |
| Premature infants (28–36 wk gestation) | 0.7–27 |
| 1–4 days | 1.0–39 |
| 2–20 wk | 1.7–9.1 |
| 5 mo–20 yr | 0.7–6.4 |
| Adults | |
| 21–54 yr | 0.4–4.2 |
| 55–87 yr | 0.5–8.9 |
| Pregnancy | |
| First trimester | 0.3–4.5 |
| Second trimester | 0.5–4.6 |
| Third trimester | 0.8–5.2 |