Iodine, Serum

Casandra

Casandra Test Code AR81858Version 1 (DRAFT)

Performing Lab

Lab ARUP LaboratoriesLab Test ID 2007463CPT Code 83018

Also known as: IODINESER

Clinical Use

Order Test

Use

The Iodine, Serum test is recommended for determining iodine excess and monitoring iodine overload in patients administered iodine-containing medications. It measures total iodine from all iodine-containing species in the specimen but does not specify the chemical form. Values above 250 µg/L may indicate iodine overload, which can occur due to contamination or administration of iodine-based contrast media. It helps in assessing iodine overload but is not the primary choice for assessing nutritional iodine status, for which the Iodine, Urine test is preferred.

Special Instructions

Patients should avoid dietary supplements and nonessential medications for 48 hours prior to specimen collection due to the potential for interfering substances. Use of iodine-based disinfectants during venipuncture should be avoided. If contamination is suspected, a second specimen collected in a certified metal-free tube is advised for confirmation.

Limitations

The test cannot distinguish between different iodine-containing species within the serum; only total iodine levels are reported. Items such as diet, medication, and supplements can introduce substances that interfere with test results. Contamination, especially from non-metal-free collection tubes, can lead to falsely elevated iodine readings. Delays in separating the serum from clot or using incorrect specimen containers can invalidate the sample.

Test Details

New York Approved

Methodology

Mass Spectrometry

Biomarkers

Iodine

Analyte

Total Iodine • Concentration / Level • Quantitative (Continuous) (e.g., copies/mL, % expression)

LOINC Codes

Order Codes

2494-3

Result Turnaround Time

1-5 days

Specimen

Serum

Volume

2 mL

Minimum Volume

0.5 mL

Container

ARUP Trace Element-Free Transport Tube

Collection Instructions

Separate from cells ASAP or within 2 hours of collection. Transfer serum directly into the transport tube avoiding transfer of cellular components.

Patient Preparation

Patients should discontinue nutritional supplements, vitamins, minerals, and nonessential medications for 48 hours prior to testing.

Storage Instructions

Refrigerated.

Causes for Rejection

Specimens not in trace element-free tubes, separators, or not separated from the clot within 2 hours; collected within 48 hours post-contrast media administration.