Common Laboratory (LAB) Values [ T ]

T3 (Triiodothyronine) Free (serum)	T3 (Triiodothyronine) Reverse (RT3) (serum)
T3 (Triiodothyronine) Total (serum)	T4 (thyroxine) Free (serum)
T4 (thyroxine) Total (serum)	Testosterone - total (serum)
Thrombin time (plasma)	Thyroglobulin (serum)
Thyroid-stimulating hormone (TSH) (serum)	Thyroxine-binding globulin (TBG) (serum)
Thyroid Function Tests	Transferrin (serum)
Triglycerides (serum)

< T >

Lab (Specimen)

Conventional Units

SI Units

T₃(Triiodothyronine) Free (serum)

0-6 years: 2.4 -4.2 pg/mL
7-17 years: 2.9-5.1 pg/mL
> 18 years old: 2.3- 4.2 pg/mL

3.5 - 6.5 pmol/L

T₃(Triiodothyronine) Reverse (RT3) (serum)

Birth-6 days: 600 -2500 pg/mL
> 7 days old: 90 -350 pg/mL

Adults: 0.11 - 0.32 ng/ml
0.04 - 0.29 nmol/L

T₃(Triiodothyronine) Total (serum)

Cord blood: 14 -86 ng/dL
1-7 days: 100 -470 ng/dL
8- 364 days: 105 -245 ng/dL
1 -9 years: 94 -269 ng/dL
10-19 years: 102 -200 ng/dL
> 20 years old: 80 -200 ng/dL

Adults: 0.8 - 2.0 ng/ml
0.9 - 2.8 nmol/L

T₄ (thyroxine) Free (serum)

0.8 - 1.8 ng/L

10 - 23 pmol/L

T₄ (thyroxine) Total (serum)

4.5 - 12.5 µg/dL

58 - 161 nmol/L

Testosterone - total (serum)

Male: 300 to 1000 ng/dL
Female: < 62 ng/dL

ALT:
Male:
14-15 yr: 33-585 ng/dL
16-17 yr: 185-886 ng/dL
18-39 yr: 400-1080 ng/dL
40-59 yr: 350-890 ng/dL
> 60 yr: 350-720 ng/dL

Tanner Stage IV: 165-854 ng/dL
Tanner Stage V: 194-783 ng/dL

Male: 6.7 - 28.9 nmol/L
Female: < 2.1 nmol/L

Thrombin time (plasma)

10 - 13.5 sec

Thyroglobulin (serum)

</= 60 ng/mL

</= 60 µg/L

Thyroid-stimulating hormone (TSH) (serum)

0.5 - 4.70 µIU/mL

American Association of Clinical Endocrinologists guidelines changed their normal range for TSH to 0.3 - 3.04 mIU/L.

0.5 - 4.70 mIU/L

Thyroxine-binding globulin (TBG) (serum)

16 - 34 mg/L

Thyroid Function Tests
Alternative source:

Thyroid Function Testing

Thyroid Function Test	Measurement	Normal Range
Total T4 (TT4)	bound and free T4	4.5 -11.5 mg/dL
Free T4 (FT4)	free T4	0.8 -2.8 ng/dL
Free T4 Index (FT4I)	estimate of free T4 FT4I = TT4 x RT3U	1.0 -4.3 U
Total T3 (TT3)	bound and free T3	75 -200 ng/dL
Resin T3 Uptake (RT3U)	binding capacity of TBG	25 -35%
TRH	TRH	5 -25 mIu/mL
TSH	TSH	0.3 - 5.0 U/mL
Thyroglobulin	Thyroglobulin	5-25 ng/mL
Radioactive Iodine Uptake (RAIU)	Distribution of radiolabeled iodine in the thyroid	5 hr – 5 to 15% 24 hr – 15 to 35%

Notes:
Free T4 - much more useful then total T4 (e.g. interested in unbound or active form). Total T4 not commonly measured. Greatly affected by TBG.
Free T4 index: indirect measure of free T4. Corrects for high/low values of TBG.
Total T3: not as useful as free T3, however, may be useful in locating problems with TBG, or if looking for problems with peripheral conversion of T4 to T3.
Resin T3 Uptake: if low, then TBG binding capacity is high. Opposite if high.
TSH: best measure to determine thyroid function.
Thyroglobulin: nonspecific test that is elevated when the thyroid gland is inflamed or enlarged.

Transferrin (serum)

188 - 341 mg/dL

1.88 - 3.41 g/L

Triglycerides (serum)

NML: 30-149 mg/dL

Normal: < 150 mg/dL.
Borderline-high:
150 to 199 mg/dL
High: 200 to 499 mg/dL
Very High: >499 mg/dL

<2.26 mmol/L (<200 mg/dL)

Important Notes

>Unless noted, all values are for adults.
>All laboratory values listed are method dependent (Methods include: immunoassay, colorimetry, electrophoresis, HPLC, etc).
>Values may vary between laboratories.