Thyroid Stimulating Hormone (TSH), Reflexive
Label Mnemonic: TSHR
Epic Lab Code: LAB840
Downtime Form: A-1a General Laboratory Requisition
Chemistry
6240 RCP
356-3527
Specimen(s):
Plasma
Collection Medium:
Plasma Separator Tube 4.5 mL
Alternate Collection Media:
Call laboratory for additional acceptable specimen collection containers.
Minimum:
3 mL whole blood in light green top or THREE Microtainer® devices.
Testing Schedule:
24 hrs/day, 7 days a week, including holidays.
Turn Around Time:
1 hour (upon receipt in laboratory)
Reference Range:
  AGE MALES AND FEMALES 1 - 11 months 0.8-6.3 μIU/mL 1 - 5 years 0.7-5.9 μIU/mL > 5 years Same as adult values Adults 0.27-4.20 μIU/mL
Comments:
Refer to BD Microtainer® Tubes product sheet for detailed sample collection instructions.

If TSH is outside the adult reference range, a Free T4 is automatically analyzed, at an additional charge to the patient.

This test is also performed in the Iowa River Landing (IRL) clinical laboratory (for specimens drawn at that site).
Test Limitations:
The assay is unaffected by icterus (bilirubin is less than 41 mg/dL), hemolysis (Hb is less than 1000 mg/dL), lipemia (Intralipid is less than 1500 mg/dL) and biotin is less than 25 ng/mL (criterion: recovery within plus or minus 10% of initial value). In patients receiving therapy with high biotin doses (i.e. is greater than 5 mg/day) no sample should be taken until at least 8 hours after the last biotin administration. No interference was observed from rheumatoid factor (up to 3250 U/mL) and samples from dialysis patients. There is no high-dose hook effect for TSH concentrations up to 1000 μIU/mL. In vitro tests were performed on 26 commonly used pharmaceuticals. No interference with the assay was found. As with all tests containing monoclonal mouse antibodies, erroneous findings may be obtained from samples taken from patients who have been treated with monoclonal mouse antibodies or have received them for diagnostic purposes. In rare cases, interference due to extremely high titers of antibodies to ruthenium can occur. TSH reagent contains additives which minimize these effects. Extremely high titers of antibodies to streptavidin can occur in isolated cases and cause interference. For diagnostic purposes, the TSH findings should always be assessed in conjunction with the patient's medical history, clinical examination and other findings.
Methodology:
Electrochemiluminescence Immunoassay
CPT Code:
84443