Non-Protein Nitrogens (NPNs)

Urea

The NPN present in the highest concentration in blood

• Major excretory product of protein metabolism

Glomerulus

After urea is carried in the blood to the kidney, it is then readily filtered from the plasma by the:

• Renal function and perfusion

• Protein content of your diet

• Rate of protein catabolism

The concentration of urea in the plasma is determined by:

Azotemia

An elevated concentration of urea in the blood is termed:

Uremia

Very high plasma urea concentration accompanied by renal failure is called:

Distal tubules

Uric acid is filtered by the glomerulus and secreted by the ____________ in the urine.

Proximal tubules

Urea is mostly reabsorbed in:

• Liver disease

• Defective tubular reabsorption (Fanconi)

• Chemotherapy

• Allopurinol overtreatment

Decreased concentration of urea

Creatinine / Creatine

It is excreted in plasma at a constant rate related to muscle mass

10:1 to 20:1

What is the normal BUN/Creatinine ratio?

>20:1

In prerenal disease, the BUN/Creatinine ratio can reach:

True renal disease

Both BUN and creatinine rise together in:

Ammonia

Formed through the deamination of amino acids during protein metabolism

Free ammonia

What type of ammonia is toxic?

Potentiometry

What is the principle of ammonia electrode?

Lloyd’s reagent (Aluminum silicate)

In the Jaffe reaction for creatinine determination, Fuller’s earth may be used as an adsorbent. Another adsorbent that can be used for the same purpose is:

Indirectly related

What is the relationship between GFR and creatinine levels?

Directly proportional

What is the relationship of the severity of kidney disease and creatinine levels?

2.14

Urea nitrogen concentration is converted to urea concentration by multiplying: