1 The hypothalamus, pituitary gland, and the gonads (ovaries, testicles) operate in a feedback loop, producing and maintaining the levels of sex hormones (androgens and estrogens) that are mainly responsible for the primary and secondary changes of puberty.
Calculation: Here is the formula for FIP: FIP = ((13*HR)+(3*(BB+HBP))-(2*K))/IP + constant. The constant is solely to bring FIP onto an ERA scale and is generally around 3.10. You can find historical FIP constant values here, or you can derive the constant yourself.
A more precise measure of the kidney function can be estimated by calculating how much creatinine is cleared from the body by the kidneys. This is referred to as creatinine clearance and it estimates the rate of filtration by kidneys (glomerular filtration rate, or GFR). The creatinine clearance can be measured in two ways. It can be calculated (estimated) by a formula using serum (blood) creatinine level, patient's weight, and age.