Search our extensive Laboratory Test Directory to find test codes, ordering recommendations, specimen stability information, Test Fact Sheets, and more.
Recommendations when to order or not order the test. May include related or preferred tests.
Not preferred for initial thyroid disorder screening; for initial screening, refer to Thyroid Stimulating Hormone (0070145). Order following an abnormal thyroid stimulating hormone (TSH) result to diagnose thyroid disease. In cases of suspected secondary hypothyroidism, order in conjunction with Thyroid Stimulating Hormone (0070145).
New York DOH Approval Status
Indicates whether a test has been approved by the New York State Department of Health.
This test is New York state approved.
Specimen Required
Patient PreparationInstructions patient must follow before/during specimen collection.
CollectSpecimen type to collect. May include collection media, tubes, kits, etc.
Serum separator tube or plasma separator tube. Also acceptable: Green (lithium heparin), lavender (K2EDTA or K3EDTA ) or pink (K2EDTA).
Specimen PreparationInstructions for specimen prep before/after collection and prior to transport.
Allow specimen to clot completely at room temperature. Separate serum or plasma from cells ASAP or within 2 hours of collection. Transfer 1 mL serum or plasma to an ARUP standard transport tube. (Min: 0.5 mL)
Storage/Transport TemperaturePreferred temperatures for storage prior to and during shipping to ARUP. See Stability for additional info.
Refrigerated.
Unacceptable ConditionsCommon conditions under which a specimen will be rejected.
Grossly hemolyzed specimens.
RemarksAdditional specimen collection, transport, or test submission information.
StabilityAcceptable times/temperatures for specimens. Times include storage and transport time to ARUP.
After separation of cells: Ambient: 5 days; Refrigerated: 1 week; Frozen: 1 month
Methodology
Process(es) used to perform the test.
Quantitative Electrochemiluminescent Immunoassay
Performed
Days of the week the test is performed.
Sun-Sat
Reported
Expected turnaround time for a result, beginning when ARUP has received the specimen.
Within 24 hours
Reference Interval
Normal range/expected value(s) for a specific disease state. May also include abnormal ranges.
Effective February 22, 2022
Free Thyroxine, ng/dL
0-3 days
0.7-2.7 ng/dL
4-30 days
0.8-3.1 ng/dL
1-23 months
0.5-2.3 ng/dL
2-6 years
0.9-1.8 ng/dL
7-11 years
0.9-1.7 ng/dL
12-19 years
0.9-1.6 ng/dL
20 years and older
0.9-1.7 ng/dL
Pregnancy, 1st Trimester
0.9-1.4 ng/dL
Pregnancy, 2nd Trimester
0.7-1.3 ng/dL
Interpretive Data
May include disease information, patient result explanation, recommendations, or details of testing.
Compliance Category
FDA
Note
Additional information related to the test.
Hotline History
N/A
CPT Codes
The American Medical Association Current Procedural Terminology (CPT) codes published in ARUP's Laboratory Test Directory are provided for informational purposes only. The codes reflect our interpretation of CPT coding requirements based upon AMA guidelines published annually. CPT codes are provided only as guidance to assist clients with billing. ARUP strongly recommends that clients confirm CPT codes with their Medicare administrative contractor, as requirements may differ. CPT coding is the sole responsibility of the billing party. ARUP Laboratories assumes no responsibility for billing errors due to reliance on the CPT codes published.
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
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