Specimen

Plasma

Collection Medium:

Alternate
Collection Media:

Call laboratory for additional acceptable specimen collection 
containers.

Minimum:

2 mls whole blood in light green top or three 0.4 ml microtubes.

Testing Schedule:

24 hrs/day, 7 days a week, including holidays.

Analytic Time:

2 hours (upon receipt in laboratory)

Reference Range:

Adults: 0.27 - 4.20 uIu/ml

Comments:

Samples which are part of a TRH stimulation test should be clearly 
identified as such.

New analytical immunoassay with different reference range instituted 
4/24/00 at 1000.

Test
Limitations:

The assay is unaffected by icterus (bilirubin is less than 41 mg/dl), 
hemolysis (Hb is less than 1g/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

See also:
Thyroid Stimulating Hormone (TSH), Reflexive, Plasma