Last Modified:
8/23/2023 8:33:27 AM
Medical Necessity Documentation:
Client Notes:
Patient Preparation:
Omit usual dose of levothyroxine on day of testing
Specimen Requirements:
Four (4) - 1.0 mL serum in a SST Gold Top Tube
Collection Instructions:
- Collect baseline sample for Free T4.
- Have patient consume levothyroxine.
- Begin timing following levothyroxine consumption.
- Collect next samples at 1, 2, and 3 hours post-consumption.
Minimum Volume:
0.5 mL Serum x 4
Transport & Storage: Temperature/Stability:
Reference Range:
No Reference Range Established
Critical Ranges:
Test Comments:
Methodology:
Electrochemiluminescence Immunoassay (ECLIA)
Clinical Significance:
The Levothyroxine Absorption Test is used to investigate the cause of persistently elevated TSH in primary hypothyroid patients on levothyroxine therapy. Causes may include non-compliance with medication or levothyroxine absorption issues.
Documentation:
Custom Panel:
No
PRODUCTION SCHEDULE
Turn Around Time:
Same Day / up to 2 days
Days Performed:
Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, Saturday
Sites Performed:
Parkview Regional Medical Center
PHL Test Code:
MCHEM
Alternate Test Names:
LT4 Absorption Test; Pseudomalabsorption
Included Tests:
Pre Free T4, 1 hour Free T4, 2 hour Free T4, 3 hour Free T4
CPT Coding:
84439 x 4
Go back to the top of the page.