TSH with FreeT4 Reflex


Sunquest Code:TSHR  
Epic Code:LAB3795Epic Name:TSH with FreeT4 Reflex
Synonyms:Thyrotropin, Reflex; Thyroid Stimulating Hormone; TSHR
Methodology:Chemiluminescence
CPT Code:84443
Turnaround Time:Varies by site.


Collection Instructions

Specimen:Blood
Optimal Volume:2.5 mL
Minimum\Peds Volume:0.6 mL
Container:Green (lithium heparin, gel) (Green (lithium heparin) on ICE, Green (sodium heparin, no gel) on ICE, Purple (EDTA), Purple (EDTA) on ICE, Red (no gel), Red or gold (gel))
Contraindications:Large doses of biotin (10 mg or more per day) may cause clinically significant interference in TSH levels. If interference is suspected, it is strongly recommended that biotin is discontinued for at least one week prior to retesting.


Processing and Shipping

Specimen Processing:Centrifuge and aliquot 1.25 mL, 0.2 mL minimum. Store in refrigerator.
Shipping Instructions:Ship at refrigerated temperature.
Stability:7 days refrigerated, indefinitely frozen.
Test Performed at or Referral Lab Chemistry  (University of Minnesota Health Maple Grove Clinics, Fairview Range - FRMC, UMMC-East Bank, Oxboro Bloom, Fairview Lakes - FLMC, Fairview Ridges - FRH, Fairview Northland - FNMC, Fairview Southdale - FSH, UMMC/UMMCH-West Bank)


Interpretive

Critical Range:0-3 years: Greater than 23 mIU/L
Reference Range:
  TSH
Age mIU/L
0-3 d 1.0-20.0
4-30 d 0.5-6.5
31 d - 5 mo 0.5-6.0
6 mo & older 0.4-4.0


FT4
Male  
Age ng/dL
0-3 d 0.97-1.87
4-30 d 0.78-1.52
1 mo & older 0.76-1.46
 
Female  
Age ng/dL
0-3 d 0.93-1.44
4-30 d 0.81-1.44
1 mo & older 0.76-1.46
Use:

 

TSH
Patients Without Pituitary Disease

 

 

 

 

 

 

 

 

< 0.4

 

0.4-4.0

 

>4.0

¯

 

¯

 

¯

Suspect hyperthyroid

 

No metabolic thyroid disease

 

Suspect hypothyroid

¯

 

¯

 

¯

Free T4

 

No further testing

 

Free T4

 

 

 

 

 

 

Thyroid gland function testing is based upon the normal response of the pituitary gland to decreased or increased levels of thyroid hormones, principally triidothyronine (T3) and thyroxine (T4). Pituitary and/or hypothalamic hypothyroidism may not be detected through this algorithmic approach and requires both TSH as well as FT4 measurements.

 



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