Test Code THSCM Thyroid Function Cascade, Serum
Additional Codes
MLAB: YEH
Powerchart: Thyroid Function Cascade
Epic: LAB3499 Thyroid Function Cascade
Reporting Name
Thyroid Function Cascade, SUseful 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 thyroid-stimulating hormone (TSH) is <0.3 mIU/L, then free T4 (FT4) is performed at an additional charge.
If FT4 is normal and the TSH is <0.1 mIU/L, then T3 is performed at an additional charge.
If TSH is >4.2 mIU/L, then FT4 and thyroperoxidase antibodies are performed at an additional charge.
See Thyroid Function Ordering Algorithm in Special Instructions.
Performing Laboratory

Specimen Type
SerumSpecimen Required
Patient Preparation: In patients receiving therapy with high biotin doses (ie, >5 mg/day), no specimen should be taken until at least 8 hours after the last biotin administration.
Container/Tube:
Preferred: Serum gel
Acceptable: Red top
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 aliquoted 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 |
Special Instructions
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) and Time(s) Performed
Monday through Sunday; Continuously
Test Classification
This test has been cleared or approved by the U.S. Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
84443-Thyroid-stimulating hormone-sensitive (s-TSH)
84439-T4 (thyroxine), free (if appropriate)
84480-T3 (triiodothyronine), total (if appropriate)
86376-Thyroperoxidase (TPO) antibodies (if appropriate)
LOINC Code Information
Test ID | Test Order Name | Order LOINC Value |
---|---|---|
THSCM | Thyroid Function Cascade, S | 11579-0 |
Result ID | Test Result Name | Result LOINC Value |
---|---|---|
STSHC | TSH, Sensitive, S | 11579-0 |
Reject Due To
Hemolysis |
Mild OK; Gross reject |
Lipemia |
Mild OK; Gross OK |
Icterus |
Mild OK; Gross OK |
Other |
NA |
Method Name
Electrochemiluminescent Immunoassay