Synonym: Cr
Specimen : Serum
Reference Value : 0.6 - 1.2
Method : Spectrophotometer
Description
Creatinine (kree-AT-uh-nin) is a waste
product that comes from meat protein in the diet and from the normal wear and
tear on muscles of the body. Creatinine levels in the blood can vary, and
each laboratory has its own normal range. In many labs the normal range is
0.6 to 1.2 mg/dL. Higher levels may be a sign that the kidneys are not
working properly. As kidney disease
progresses, the level of creatinine in the blood increases.
Indications
Evaluated known or suspected impairment of renal function ( decrease glomerular filtration rate (GFR)
Interpretation
Increase in :
- Renal disease , acute and chronic renal failure .
- Congestive heart failure .
- Dehydration .
- Acute myositis.
- Hyperthyroidism .
- Shock .
Decrease in :
- Decrease muscle mass owing to debilitating disease or increasing age .
- Inadeque protein intake .
- Liver disease ( sever) due to decreasing creatine production .
- Muscular dystrophy .
Blood urea nitrogen (BUN).
Synonym : BUN
Specimen : Serum or Plasma
Reference Value : 8 - 20 mg/dL
Method : Spectrophotometer
Description
Urea nitrogen (yoo-REE-uh
NY-truh-jen) also is produced from the breakdown of food protein. A normal
BUN level is between 7 and 20 mg/dL. As kidney
function decreases, the BUN level increases.
Indications :
- Evaluated renal function
- Evaluated liver function
- Evaluated hydration
Interpretation
Increase in
- Acute renal failure .
- Chronic glomerulonephritis
- Congestive heart failure.
- Decrease renal perfusion
- Diabetes .
- Increase protein catabolism
- Excessive protein ingestion
- Gastrointestinal bleeding .
- Hypovolemia
- Nephrotoxic agents
- Pyelonephritis
- Shock
- Urinary tract obstruction .
- Increase production of urea .
- Early prerenal azotemia
Decrease in :
- Inadequate dietary protein
- Low- protein / high - carbohydrates diet
- Malabsorption syndromes
- Sever liver disease
- Polyuria .
Urine Tests
Some urine tests require only a few ounces of urine. But some tests
require collection of all urine produced for a full 24 hours. A 24-hour urine
test shows how much urine your kidneys produce in 1 day. The test is
sometimes used to measure how much protein leaks from the kidney into the urine in 1 day. However,
protein leakage can also be accurately determined in a small sample of urine
by measuring its protein and creatinine concentration.
Creatinine
Clearance
Specimen : Urine (5 mL ) from an unpressed random or timed specimen collected in a clean plastic collection container .
Reference value : Adults 90 - 130 mL/min/1.73m2
Method : Spectrophotometer
A creatinine clearance test compares the creatinine in a 24-hour
sample of urine to the creatinine level in the blood, to show how many
milliliters of blood the kidneys are filtering out each minute (mL/min). The
creatinine clearance can also be estimated accurately from the serum
creatinine alone using well established prediction equations.
Indications
- Determination the extent of nephron damage in known renal disease .
- Determination renal function before administering nephro toxic drugs .
- Evaluated glomerular functions
- Monitor effectivenessof treatment in renal disease .
Interpretation
Increase in
- High cardiac output .
- Exercise
- Acromegaly
- Diabetes mellitus ( early stage )
- Infections ,
- Hypothyroidism
Decrease in
- Acute or chronic glomerulonephrities .
- Acute or chronic renal failure
- Decrease renal blood flow ( shock , hemorrhage, dehydration , CHF )
- Drugs : nephrotoxic drugs
- Muscle wasting disease .
- Urinary tract obstruction ( e.g , from calcuii )
