Diagnosis+and+Diagnostic+Tests

**Diagnosis.**

 * Hypothyroidism is diagnosed based upon T4 levels in the body. The disease is often suspected when results for TH levels come back and are significantly lower than the expected values. Although diagnosing hypothyroidism is most often made based on TH and TSH levels in the blood, clinical manifestations are likely to also present themself. Due to hypothyroidism being an endocrine disease, it has affects on many of the body systems. Some of these manifestations include goiter, myxedema (an altered condition of the skin), intolerance to cold, a lowered metabolic rate, as well as tiredness. (Huether, S., McCance, K., 2008). Patients may also experiene changes in their mental status which may present as slower speech patterns, and alterations in memory capabilities. Along with having affects on the brain, skin, and metabolic functions, functionality of the gastrointestinal system is also altered. GI motility decreases as a result of hypothyroidism, leading to constipation and in some instances, intestinal obstructions. Acquiring these manifestations depends on how much TSH is being secreted; however, combinations of these signs and symptoms are likely to present in some form (Lewis, S., Dirksen, S., Hietkemper, M., Bucher, L., Camera, I., 2011, pp. 1269-1270).**

**Diagnostic Tests.**

 * The most commonly used diagnositc tests to check for hypothyroidism is an assessment of TSH and free T4 levels in the blood. Health care providers will also run diagnostics on serum T3, T4, as well as a TRH stimulation test and a Thyroid Perioxidase Antibody (TPO) test. The TRH stimulation lab is conducted by injection and then reviewal of TSH levels takes place. If TSH levels have increased after this injection, then the provider knows that their may be some form of hypothalamic dysfunction. TPO tests are completed to assess the origin of the diesase--when results for this lab come back positive, it is suggested that the origin for hypothyroidism is autoimmune related. Some of the other tests that may also be conducted include cholesterol/triglycerides, tests assessing for anemia, as well as tests checking for creatine kinase (Lewis, S., et. al., 2011, pp. 1269-1270).**
 * Expected values:**
 * Free T4: 0.8-2.7 ng/dL**
 * Total T4: 4.6-11.0 mcg/dL**
 * Total T3: 20-50 years old: 70-204 ng/dL**
 * 50 years or older: 40-181 ng/dL**
 * TSH: 0.4-4.2 mU/L**
 * Lab values lower than the expected values is an indication of secondary hypothyroidism; however, an increase in TSH levels and a decrease in T3 and T4 levels is indicative of prrimpary hypothyroidism** **(Lewis, S., et. al., 2011, p. 1798).**