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Test Code TSHR Thyroid-Stimulating Hormone (TSH), with Reflex (Thyroid Cascade)

Performing Laboratory

NRL-Chemistry

Methodology

Immunoenzymatic

Testing Algorithm:

If TSH result is <0.30 mcIUnits/mL or >4.2 mcIUnits/mL, LAB127 T4 (Thyroxine), Free will be performed, at an additional charge.

If TSH is <0.30 mcIUnits/mL and FT4 is ≤ 1.7 ng/dL, LAB137 T3 (Triiodothyronine), Free will be performed, at an additional charge.

Specimen Requirements

Submit only 1 of the following specimens:
  
Preferred:

Specimen Type: Plasma

Container/Tube: Light-green top (lithium heparin)

Specimen Volume: 1 mL

Collection Instructions:

1. Spin down unopened (vacuum intact) tube within 45 minutes of draw.

2. Label specimen as plasma.

 

Alternate (Non-Hospital Patient):

Specimen Type: Serum

Container/Tube: Gold top, serum gel

Specimen Volume: 1 mL

Collection Instructions:

1. Spin down unopened (vacuum intact) tube within 45 minutes of draw.

2. Label specimen as serum.

Reference Values

TSH

Age Reference Interval
< 4 days 1.00 - 25.00 mcIUnit/mL
4 days - 30 days 0.50 - 10.00 mcIUnit/mL
> 30 days 0.30 - 4.20 mcIUnit/mL

Free T4

  Reference Interval
  0.90 - 1.70 ng/dL

FT3

  Reference Interval
  2.0-4.4 pg/mL

 

Day(s) Test Set Up

Monday through Sunday

Turnaround Time:

STAT-2 hours

Routine-shift

Specimen Transport Temperature

Refrigerate

Test Classification and CPT Coding

84443-TSH

84439-Free T4 (if appropriate)

84481-Free T3 (if appropriate)