TSH Rfx on Abnormal to Free T4

Test ID:

704330

CPT code:

84443

Synonyms:

Thyroid Stimulating Hormone with Reflex

TSH with Reflex to Free T4

Clinical Use:

For differential diagnosis of primary, secondary, and tertiary hypothyroidism. Also useful in screening for hyperthyroidism. This assay allows adjustment of exogenous thyroxine dosage in hypothyroid patients and in patients on suppressive thyroxine therapy for thyroid neoplasia.

Specimen Type:

Serum

Requested Volume: 

1 mL

Minimum Volume: 

0.7mL

Container Type: 

Serum Separator Tube (SST®)

Patient Preparation: 

Specimen collection after fluorescein dye angiography should be delayed for at least 3 days. For patients on hemodialysis, specimen collection should be delayed for 2 weeks.

Collection:

should only be ordered on patients 1 year of age or older. Orders on patients younger than 1 year will have a TSH only performed.

Storage Instructions:

Room temperature

Stability Requirements:

Room temperature: 7 days
Refrigerated: 7 days
Frozen: 28 days

Expected Turnaround Time:

1 to 2 Days

Rejection Criteria

plasma specimen; improper labeling