T4/T3/TSH

Thyroid Gland

Most of the output of the thyroid is in the form of T4; only a small amount is in the form of T3, but T3 is much more potent than T4. The production of T4 and T3 is controlled by TSH from the anterior pituitary gland (in response to TRH in the hypothalamus)

Pancreatic Function Tests:

Pancreatic Function Tests: • Amylase: 39-170 units/L • Lipase: 7-60 units/L

T3 is not usually used to confirming the diagnosis of suspected hypothyroidism b/c other test can demonstrate hypofunction of the thyroid gland. However, a client may have clinical signs of Thyrotoxicosis with a normal T4. Then the measurement of T3 is needed, b/c T3 elevates in thyrotoxicosis while other thyroid test are still in the normal range

Reference values for T3 60-181 ng/dL

In primary hypothyroidism, TSH ___

elevated in an attempt to stimulate the failing thyroid gland

a low TSH is an indication for ____

further investigation of pituitary disorders

T4 increase in ___

hyperthyroidism

T4 decrease in ___

hypothyroidism

• BUN/Creatinine Ratio: 6-20:1

o If BUN and creatinine are both increased = renal problem o If BUN is decreased and creatinine is normal = liver problem o If BUN is increased and creatinine is normal = other problems

Renal Function Tests: • Indications for use: evaluate renal or liver function; evaluation dehydration; monitor effects of hepatotoxic/nephrotoxic drugs • BUN (blood urea nitrogen): 5-20 mg/dL

o Indicator of glomerular filtration o Increased with renal disease, high protein diet, GI bleed, hypovolemia, dehydration, some drugs o Decreased BUN: liver failure, negative nitrogen balance, nephritic syndrome, some drugs

• Serum Creatinine Level: 0.8-1.5 mg/dL

o More sensitive indicator of renal function than BUN o Not effected by liver function o Levels rise later than BUN o Suggests a more CHRONIC condition o Decrease could be from significant muscle mass decrease

Liver Function Tests:

• ALT (SGPT): less than or equal to 48 units/L • AST (SGOT): less than or equal to 42 units/L • Alkaline phosphatase: 25-150 units/L • Total bilirubin: < 1.3 mg/dL

Liver/Kidney Function:

• Albumin: 3.5-5 g/dL • Globulin 1.5-4.5 g/dL • A/G ratio 1.1-2.5 • Total Serum Protein 6-8.5 g/dL

Reference value for TSH is

0.5-5 uU/ml

Reference values for Total T4

4.5 -10.9 ug/dL

The Harris Benedict Formula is used to

• determine TOTAL DAILY CALORIE NEEDS