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Test Code THSCM Thyroid Function Cascade, Serum

Reporting Name

Thyroid Function Cascade, S

Useful For

Screening for a diagnosis of thyroid disease

Profile Information

Test ID Reporting Name Available Separately Always Performed
STSHC TSH, Sensitive, S Yes, (order STSH) Yes

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
FRT4C T4 (Thyroxine), Free, S Yes, (order FRT4) No
TPOC Thyroperoxidase Ab, S Yes, (order TPO) No
T3C T3 (Triiodothyronine), Total, S Yes, (order T3) No

Testing Algorithm

If thyrotropin (TSH, formerly thyroid-stimulating hormone) is less than 0.3 mIU/L, then free T4 (thyroxine) is performed at an additional charge.

 

If FT4 is normal and the TSH is less than 0.1 mIU/L, then T3 (triiodothyronine) is performed at an additional charge.

 

If TSH is greater than 4.2 mIU/L, then free T4 and thyroperoxidase antibodies are performed at an additional charge.

 

For more information see Thyroid Function Ordering Algorithm.

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Serum


Specimen Required


Collection Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 1.5 mL

Collection Instructions:

1. Serum gel tubes should be centrifuged within 2 hours of collection.

2. Red-top tubes should be centrifuged and the serum aliquoted into a plastic vial within 2 hours of collection.


Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time
Serum Refrigerated (preferred) 7 days
  Frozen  30 days
  Ambient  72 hours

Reference Values

0-5 days: 0.7-15.2 mIU/L

6 days-2 months: 0.7-11.0 mIU/L

3-11 months: 0.7-8.4 mIU/L

1-5 years: 0.7-6.0 mIU/L

6-10 years: 0.6-4.8 mIU/L

11-19 years: 0.5-4.3 mIU/L

≥20 years: 0.3-4.2 mIU/L

Day(s) Performed

Monday through Sunday

CPT Code Information

84443

84439 (if appropriate)

84480 (if appropriate)

86376 (if appropriate)

Report Available

1 to 2 days

Reject Due To

Gross hemolysis Reject
Gross lipemia OK
Gross icterus OK

Method Name

Electrochemiluminescent Immunoassay

Forms

If not ordering electronically, complete, print, and send a Renal Diagnostics Test Request (T830) with the specimen.