Table 1.
Number of Infants Analyzed, Thyroid Hormone Concentrations, and Ratios
| |
|
Mean ± SD |
|||||
|---|---|---|---|---|---|---|---|
| T3 |
rT3 |
T4 |
T3/rT3 |
T3/T4 |
|
||
| Group | N | ng/dL | ng/dL | μg/dL | ng/ng | ng/μg | T3/(rT3 × T4) |
| MCT8 deficient | 6 | 94 ± 18 | 32 ± 7 | 9.3 ± 2.2 | 3.04 ± 0.67 | 10.1 ± 2.3 | 0.349 ± 0.146 |
| Normal infants | 42 | 76 ± 21 | 78 ± 20 | 15.7 ± 3.6 | 1.02 ± 0.34 | 20.5 ± 4.7 | 0.067 ± 0.027 |
| Normal infants (DBS stored >1 year) | 16 | 119 ± 42 | 130 ± 47 | 8.7 ± 2.1 | 0.96 ± 0.31 | 7.8 ± 2.2 | 0.117 ± 0.049 |
| Prematurely born | 34 + [8] | 57 ± 30 | 131 ± 56 | 7.9 ± 3.1 | 0.50 ± 0.35 | 21.1 ± 18.4 | 0.071 ± 0.063 |
| Normal infants (DBS collected at day 1) | [10] | 80 ± 22 | 137 ± 55 | 9.2 ± 3.0 | 0.64 ± 0.20 | 11.8 ± 3.8 | 0.075 ± 0.031 |
Numbers in square brackets are samples from the United States.
DBS, dried blood spot; MCT8, monocarboxylate transporter 8; N, number of DBS; rT3, reverse T3; SD, standard deviation; T3, triiodothyronine; T4, thyroxine.