Thyroid Hormone Toxicity Workup

Updated: Apr 29, 2022
  • Author: Amanda Lu, MD; Chief Editor: Asim Tarabar, MD  more...
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Laboratory Studies

Most asymptomatic patients do not require diagnostic testing, especially very early after exposure.

The following tests are indicated in symptomatic patients:

  • Complete blood cell count

  • Electrolytes (eg, calcium, magnesium, phosphorous)

  • Urinalysis

  • Serum acetaminophen level (in patients with intentional exposures and suicidal ideations)

  • T3, T4, and T3 resin uptake (RU) levels may be sent 2-6 hours postingestion; however, remember the following:

    • These levels offer no aid in the acute phase of clinical management.

    • These levels are of no value in determining prognosis.


Other Tests and Procedures

Other tests

Electrocardiography is indicated to evaluate symptomatic patients for myocardial ischemia, myocardial infarction, and cardiac dysrhythmias (eg, atrial fibrillation, supraventricular tachycardia).


Lumbar puncture (LP) should be considered in patients with hyperthermia and change of mental status to rule out CNS infection.