Thyroid stimulating hormone (TSH)

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Test Name:

Thyroid stimulating hormone (TSH)

Synonyms:

Thyrotropin

Ordering Information:

If test ordered is . . .	then, . . .
Thyroid stimulating hormone (TSH)	only TSH will be performed. No testing of free thyroid hormones will be automatically reflexed.
Thyroid stimulating hormone (TSH) progressive (aka PTSH, TSHP)	automatic reflex testing will occur if indicated, as outlined below.

Collection Device/Tube Type:

1. EDM Base Lab: 5 mL blood - GOLD SST (gel)
2. CGY DSC: 4.5 mL blood - MINT LIHEP PST (gel)
3. NOTE: The preferred tube type at each testing site is acceptable at the alternate site

Submission Requirements:

1 mL serum or lithium heparin plasma

Frequency of Testing:

Daily

Reference Range:

Age	TSH (mIU/L)
0 to < 8 days	1.23 – 25.00
8 days to < 1 year	1.00 – 6.80
≥ 1 year	0.20 – 6.50

Note: For interpretation of the test results in pregnancy, refer to the care pathway at Thyroid Function in Pregnancy

Comments:

Thyroid stimulating hormone (TSH) progressive is the preferred test for initial screening to assess thyroid function.

When thyroid stimulating hormone (TSH) progressive is ordered:
• If TSH is < 0.10 mIU/L, a free T4 (FT4) will be automatically reflexed
• If a reflexed FT4 is low or normal, a free T3 (FT3) will be automatically reflexed

For testing referred to Edmonton Base Lab:
Serum is the preferred specimen type for TSH, progressive because the algorithm may include automatic reflex of Free T4. It has been noted that Free T4 results are approximately 20% higher in plasma compared to serum. A comment reflecting this positive bias will be appended to Free T4 results from plasma samples, as the Free T4 reference range was established from serum samples.

Last Reviewed:

04 May 2023

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