Table 6.
Infant TH levels
| TSH | T3 | T4 | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Reference | Author Country Year |
Time point of TH measurement | Number | Median | Range | Median | Range | Median | Range | |||
| Normal reference range | 1–7 days✦ | TSH (mIU/L) ✦ |
Lower limit: 0.13–1.79 Upper limit: 9.23–57.2 |
– | – | FT4 (pmol/L) ✦ |
Lower limit: 8.9–20.3 Upper limit: 26.8–46.6 |
|||||
| [38] |
Kato Japan 2016 |
4–7 days postpartum (heelprick) | 392 | TSH (mIU/L)* | 2.2 | LOD–7.9 a | FT4 (pmol/L) *, d | 26.1 | 17.9–37.2 a | |||
| [39] |
Preston USA 2018 |
3 days postpartum (heel prick) | 480 | TT4 (nmol/L)* | 222.7 | 47.6–459.5 | ||||||
| [44] |
Wang Taiwan 2014 |
At delivery (cord blood serum) | 92–116 | TSH (mIU/L)* | 6.65 | TT3 (nmol/L)* | 0.77 | TT4 (nmol/L)* | 107.7 | |||
| FT4 (pmol/L)* | 9.40 | |||||||||||
| [46] |
Yang China 2016 |
At delivery (cord blood serum) | 146–157 | TSH (mIU/L)* | 9.44 | 1.26–57.01 | TT3 (nmol/L) | 0.90 | 0.56–3.16 | TT4 (nmol/L) | 129.70 | 69.52–232.20 |
| FT3 (pmol/L) | 2.01 | 1.11–4.45 | FT4 (pmol/L) | 15.88 | 9.44–21.26 | |||||||
| [47] |
Xiao Faroe Island 2019 |
At delivery (cord blood serum) | 153 | TSH (mIU/L)*, e | 6.98b | 2.03–27.40 | FT3 (pmol/L) | 2.35b | 2.00–5.54 | T4 (nmol/L) | 129.07b | 68.00–205.00 |
| T3RU | 0.83b | 0.54–1.05 | FT4 (pmol/L) | 11.93b | 0.38–16.60 | |||||||
| FT4I (IU/L) | 107.60b | 65.00–191.00 | ||||||||||
| [48] |
Dufour Belgium 2018 |
3 days postpartum (heel prick) | 214 | TSH (mIU/L) | 4.85 | Max: 16.6 | ||||||
| [49] |
Shah-Kulkarni Korea 2016 |
At delivery (cord blood serum) | 279 | TSH (mIU/L)* | 8.3 | 1.2–49.6 | TT3 (nmol/L)* | 0.88 | 0.59–2.22 | TT4 (nmol/L)* | 108.1 | 61.8–168.6 |
| [50] |
De Cock Netherland 2014 |
4–7 days postpartum (heel prick) | Boys: 52 | TT4 (nmol/L) | 85.6 | 42–138 | ||||||
| Girls: 31 | TT4 (nmol/L) | 89.6 | 68–117 | |||||||||
| [51] |
Tsai Taiwan 2017 |
At delivery (cord blood plasma) | 118 | TSH (mIU/L)* | 2.92 c | 0.008–14.1 | TT3 (nmol/L)* | 0.46c | 76.3–202.8 | TT4 (nmol/L)* | 115.6 c | 164.8–1530.5 |
| FT3 (pmol/L)* | 2.29 c | 1.54–5.7 | FT4 (pmol/L)* | 15.4 c | 10.3–29.6 | |||||||
| [52] |
Aimuzi China 2019 |
At delivery (cord blood serum) | 568 | TSH (mIU/L) | 4.66 | 1.73–28.87 | FT3 (pmol/L) | 2.03 | < LOD-4.29 | FT4 (pmol/L) | 13.48 | < LOD-18.44 |
TT3 (total triiodothyronine), FT3 (free triiodothyronine), TT4 (total thyroxine), FT4 (free thyroxine), FT4I (free thyroxine index); T3RU (Free triiodothyronine resin uptake), ✦: Correct to Onsesveren et al 2017; 10.21820/23987073.2017.6.22 based on review of 35 studies of TSH and FT4 in childhood, *: Converted values, for TSH all values are converted to mIU/L, for TT3 and TT4 all values are converted to nmol/L, for FT3 and FT4 all values are converted to pmol/L, a: 95% confidence interval,b: Geometric mean, c: Mean, d: In the article the value reported were 2.03 ng/mL, converted to pmol/L giving 2613 pmol/L; other FT4 values from the same cohort (Minatoya et al. 2017) have reported similar values in ng/dL. We believe that the correct unit is 2.03 ng/dL (=26.1 pmol/L), which gives more normal FT4 levels, e: Values were reported as IU/L, we choose to interpret the values as μIU/mL / mIU/L as the values are then in the normal range and comparable with values reported from other studies