Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (875 page)

   Animal meat diet

Decreased In

   Hyperthyroidism

   Anemia

   Muscular dystrophy

   Decreased muscle mass

   Advances renal disease

   Leukemia

   Vegetarian diets

   Limitations

   Urine creatinine is not ordered alone. Creatinine clearance, which requires a serum creatinine, offers useful renal function data. Serum creatinine alone is not an adequate index of glomerular filtration rate.

   Twenty-four–hour urine creatinine levels are used as an approximate check on the completeness of 24-hour urine collection.

CRYOFIBRINOGEN

   Definition

   Cryofibrinogen is an abnormal complex of proteins that precipitate out of plasma as it is cooled. These cold, insoluble protein complexes can be composed of fibrin, fibrinogen, and fibrin split products, in conjunction with other plasma proteins. If refrigerated serum and plasma both form a precipitate, then the precipitated proteins are referred to as cryoglobulins (see below). If, however, precipitation develops after refrigeration of plasma but does not occur in cold serum, the plasma precipitate is referred to as cryofibrinogen. Cryofibrinogenemia can be a primary (essential) condition or it may arise in association with an underlying condition, such as malignancy, infection, inflammation, diabetes, pregnancy, scleroderma, or oral contraceptives. A few familial cases have been reported. Skin biopsies may show leukocytoclastic vasculitis. Morbidity associated with cryofibrinogenemia occurs as the result of thrombotic occlusion of the small to medium arteries by insoluble protein complexes. Most individuals with cryofibrinogenemia are asymptomatic.