Body Mass Index
A general indicator of the body fat an individual is carrying based upon the ratio of weight to height.
Body Surface Area
A measure of the 2-dimensional extent of the body surface (i.e., the skin).
Body surface area (BSA) can be calculated by mathematical formula or from a chart that relates height to weight. BSA is often an important factor in dosing.
Resting Energy Expenditure
Estimated daily caloric needs at rest for a given weight, height, gender and age.
Weight for BMI 27
Weight for adults at which health risk related to being overweight starts to increase.
Lean body mass
Total body weight minus fat content; the weight of bones, muscles and organs.
Fractional excretion of sodium
To accurately interpret FENa, patients should not have recently received diuretics.
FENa is greater than 1% and usually greater than 3% with acute tubular necrosis and severe obstruction of the urinary drainage of both kidneys. It is generally less than 1% in patients with acute glomerulonephritis, hepatorenal syndrome, and states of prerenal azotemia such as congestive heart failure or dehydration. FENa may also be less than 1% with acute partial urinary tract obstruction. -- Stein JH, ed. Internal Medicine, 4th edition. Mosby-Year Book. 1994.
Glomerular Filtration Rate (MDRD)
The MDRD formula best estimates GFR from creatinine in middle aged patients, black patients, those with diabetic nephropathy and those who have undergone renal transplant.
MDRD is an acronym for Modification of Diet in Renal Disease. As with the C-G formula, the MDRD formula is most accurate if renal function has been relatively stable.
Glomerular Filtration Rate (CG)
Cockroft–Gault best estimates GFR from creatinine in older patients and for general screening.
As with the MDRD formula, the C-G formula is most accurate if renal function has been relatively stable.
Glomerular Filtration Rate (Schwartz)
The Schwartz equation best estimates GFR from creatinine in children.
Alveolar (A) to arterial (a) Gradient
High gradients (over 10 mmHg) are a result of impaired diffusion, or by ventilation-perfusion mismatch (shunting).
Another estimate of normal A-a gradient is: (ageY/ 4) + 4.