CPT Code: 84443
Order Code: 90896
ABN Requirement: No
Specimen: Serum
Volume: 1.0 mL
Minimum Volume: 0.7 mL
Container: Gel-barrier tube (SST)
Collection:
- Collect and label sample according to standard protocols.
- Gently invert tube 5 times immediately after draw. DO NOT SHAKE.
- Allow blood to clot 30 minutes.
- Centrifuge for 10 minutes.
Special Instructions: Specimen collection after fluorescein dye angiography should be delayed for at least 3 days. According to the assay manufacturer Siemens: “Samples containing fluorescein can produce falsely depressed values when tested with the Advia Centaur TSH assay.” For patients on hemodialysis, specimen collection should be delayed for 2 weeks.
Transport: Store serum at 2°C to 8°C after collection and ship the same day per packaging instructions included with the provided shipping box.
Stability:
Ambient (15-25°C): 7 days
Refrigerated (2-8°C): 7 days
Frozen (-20°C): 28 days
Causes for Rejection: Specimens other than serum; improper labeling; samples not stored properly; samples older than stability limits
Methodology: Immunoassay (IA)
Turn Around Time: 1 to 3 days
Reference Range:
| Pregnancy | mIU/L |
|---|---|
| First Trimester | 0.26-2.66 |
| Second Trimester | 0.55-2.73 |
| Third Trimester | 0.43-2.91 |
Results are flagged based on the first trimester assay-specific reference interval. For later stages of pregnancy, interpret results based on the trimester-specific reference intervals provided.
Clinical Significance: TSH levels are lower during pregnancy, especially during the 1st trimester. Based on recent clinical studies which have shown that even mildly elevated TSH during pregnancy is associated with adverse pregnancy outcomes, the American Thyroid Association has released clinical guidelines which recommend the use of assay-specific and trimester-specific reference intervals.
The CPT codes provided are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.