THYROXINE

Mnemonic

TT4

Synonym

Total T4 - Tetraiodothyronine

Specimen Collection Requirements

Collect

Lithium Heparin, Sodium Heparin, K3-EDTA, or Sodium Citrate tube.

Serum is also acceptable.

Handling

Allow serum to clot completely at room temperature (minimum: 30 minutes).

Centrifuge and separate plasma or serum from cells ASAP.

Note: If sodium citrate plasma is used, results must be corrected by 10%, due to dilution of the anticoagulant.

Preferred Volume

1.0 mL

Minimum Volume

0.3 mL

Transport

Refrigerated (2-8°C)

Rejection Criteria

Grossly hemolyzed specimens.

Stability

AFTER SEPARATION FROM CELLS: Ambient (20-25°C): 8 hours; Refrigerated (2-8°C): 4 days; Frozen (at or below -20°C): 2 months

Testing Information

Method

Chemiluminescent Immunoassay

Referral Lab

Samaritan Health Services-SPCH

Reference Values

Reference Values

4.0-12.0 µg/dL

CPT Codes

84436

Last Updated: Thursday, January 5, 2017 03:42:31 AM