Labs Flashcards
What do creatine kinase levels tell you?
creatine + ATP phosphocreatine + creatinine
catalyzed by creatine kinase
increased CK = muscle destruction
What do creatinine levels tell you?
creatine + ATP phosphocreatine + creatinine
catalyzed by creatine kinase
Kidney function.
Creatinine is removed from the blood chiefly by the kidneys, primarily by glomerular filtration, but also by proximal tubular secretion. Little or no tubular reabsorption of creatinine occurs. If the filtration in the kidney is deficient, blood creatinine concentrations rise. Therefore, creatinine concentrations in blood and urine may be used to calculate the creatinine clearance (CrCl), which correlates approximately with the glomerular filtration rate (GFR). Blood creatinine concentrations may also be used alone to calculate the estimated GFR (eGFR).
stool osmotic gap
290 - 2 (stool Na+ + stool K+)
Stool osmotic gap is a measurement of the difference in solute types between serum and feces, used to distinguish among different causes of diarrhea.
Feces is normally in osmotic equilibrium with blood serum, which the human body maintains between 290–300 mOsm/kg. However, the solutes contributing to this total differ. Serum is mostly sodium and potassium salts (as reflected in the formulas for serum osmol gap and anion gap), while the digestive tract contains significant amounts of other compounds. Stool osmotic gap is a measure of the concentration of those other compounds.
A normal gap is between 50 and 100 mOsm/kg, corresponding to the concentration of other solutes such as magnesium salts and sugars.
A low stool osmotic gap suggests secretory diarrhea, wherein the digestive tract is hyperpermeable and losing electrolytes, while a high gap suggests osmotic diarrhea, wherein the digestive tract is unable to absorb solutes from the chyme, either because the digestive tract is hypopermeable (e.g. due to inflammation), or non-absorbable compounds (e.g. Epsom salt) are present.[4] The reason for this is that secreted sodium and potassium ions make up a greater percentage of the stool osmolality in secretory diarrhea, whereas in osmotic diarrhea, other molecules such as unabsorbed carbohydrates are more significant contributors to stool osmolality.
causes of a low stool osmotic gap (<50)
Toxin-mediated causes (cholera, enterotoxigenic strains of E. coli) and secretagogues such as vasoactive intestinal peptide (from a VIPoma, for example).
Uncommon causes include gastrinoma, medullary thyroid carcinoma (which produces excess calcitonin), factitious diarrhea from non-osmotic laxative abuse and villous adenoma.
causes of a high stool osmotic gap (>100)
Celiac sprue, chronic pancreatitis, lactase deficiency, lactulose, osmotic laxative use/abuse, and Whipple’s disease.
(Whipple’s disease is a rare systemic infectious disease caused by the bacterium Tropheryma whipplei. )
leukopenia
decreased white blood cells
neutropenia
decreased neutrophils
thrombocytopenia
decreased platelets
leukocytosis
increased WBC
thrombocytosis
invcreased platelets
neutrophilia
increased neutrophils
leukocytes vs. lymphocytes
Leukocytes are part of the body’s immune system. They help the body fight infection and other diseases. Types of leukocytes are granulocytes (neutrophils, eosinophils, and basophils), monocytes, and lymphocytes (T cells and B cells).
