I-131 Admission Guidelines Checklist

A Quick Checklist

  • Physical Examination: ideally within 30 days (and not longer than 90 days, before treatment)
    • Please Note: The size and side (R/L) of palpable thyroid nodules, any cardiac murmurs, heart rate, thorough palpation of the abdominal cavity, body weight, body condition score, and any abnormal findings.
  • Bloodwork: current, within 90 days pre-admission – we need this the week prior to treatment:
    • CBC
    • Blood Chemistry (at minimum ALT, ALP, BUN, Creatinine, Phosphorous)
      • SDMA is nice, but not necessary –most helpful to know renal status
    • Total T4 (this is key to calculating the I-131 dose)
      • Total T4 results >8, >10, >24, etc. should be run to a dilution to get an actual #
      • No oral methimazole for 1 week prior to this blood draw
      • No transdermal methimazole for 3 weeks prior to this blood draw
      • If on y/d, mix with regular diet for 3 weeks prior to this blood draw
    • Full Urinalysis
      • Specific Gravity measured by refractometer, not dipstick.
      • Otherwise, use Reference Lab add-on urinalysis.
      • UTI’s and specific gravity are important to note.
    • Blood pressure is recommended (but not required) For All Referred I-131 Patients
  • If methimazole is resumed before treatment, it must be stopped again before I-131 treatment:
    • oral methimazole stopped for 1 week
    • transdermal methimazole or y/d stopped for 3 weeks – unless the cat has a T4 > 15 and could be compromised off medication (please call to discuss particulars.)
  • Advise us if the patient has had any iodine compound (even betadine skin scrub) or holistic medications (such as kelp) within the last six months. Note – some diets now contain kelp. Ideally, kelp containing diets should be discontinued 1-2 weeks before I-131 treatment.
  • We do not routinely require thoracic radiographs or echocardiograms pre-iodine treatment, but they certainly can be performed, if indicated. Please call to consult with questions.

**If you have a borderline case, please call us at (303) 663-2287 to discuss how to perform a T3 suppression test.

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