RT3U

Alternative names:

resin T3 uptake; T3 resin uptake; T3RU

Normal values:

24% to 37%

What abnormal results mean:

Greater-than-normal levels may indicate:

• hyperthyroidism
• nephrotic syndrome
• protein malnutrition
• renal failure

Lower-than-normal levels may indicate:

• acute hepatitis
• hypothyroidism
• hypothyroidism; primary
• hypothyroidism; secondary
• pregnancy
• estrogen administration

Additional conditions under which the test may be performed:

• chronic thyroiditis (Hashimoto's disease)
• drug-induced hypothyroidism
• Graves' disease
• subacute thyroiditis
• thyrotoxic periodic paralysis
• toxic nodular goiter