Sub-clinical

Sub-clinical is a medical term referring to a disease process that has initiated but has not yet manifested symptoms.

One example is sub-clinical hypothyroidism, where a patient will manifest none of the typical symptoms of hypothyroidism, and blood tests will show a normal T3 and T4, but an elevated TSH--indicating that the thyroid gland is requiring a greater-than-normal stimulus to produce a normal level of thyroid hormone.

Another frequently cited example is a sub-clinical thiamine deficiency. A patient with a sub-clinical thimamine deficiency may have low levels of thiamine, but not be manifesting any of the symptoms. However, the administration of intravenous glucose may induce Wernicke-Korsakoff Syndrome or beri-beri by exacerbating the already underlying thiamine deficiency, as thiamine is consumed during normal glucose metabolism.