Sign in →

Test Code TSH RFLX FT4 TSH, Reflex to Free T4

Additional Codes

LAB13042

Collection Method

Venous collection

Minimum Volume

0.5ml

Container

Gold Top SST

Acceptable Specimens

Serum:

  • Gold Top SST
  • Red Top


Plasma:

  • Light Geen Top (lithium heparin)

Reference or Target Ranges

Age Male Female
< 1 month comment 1 comment 1
1 month to 18 years 0.5 - 6.0 0.5 - 6.0
> 18 years 0.27 - 4.20 0.27 - 4.20

comment 1- Pediatric reference ranges have not been established by CPH laboratory services

Reportable Units

uIU/mL

Critical Value

Not defined for this assay

Reasons for Rejection

Hemolysis Threshold 1000 mg/dL
Icterus Threshold 41 mg/dL
Lipemia Threshold 1500 mg/dL
Other QNS, contaminated, improperly Labeled, improper specimen type

Specimen Stability

Ambient 8 days
Refrigerated (4°C to 8°C) 14 days
Frozen(-40°C to 0°C) 2 years

Performance Information

Days and Time Performed 24/7
Expected Turn Around Time Stat: 1 hour
Routine: 4 hours
Stat Availability Yes
Performing Bench CPH Chemistry
Methodology/Method Description Roche Cobas

CPT Codes

84443

Last review/edit date

March 2024

Reflex Testing

TSH will reflex to FT4 if result is:

<0.270 or >4.200