1. Kidney Function Tests (KFT)

2. Related terms Nephr/o, ren/o Kidney Nephritis Hydro/o Water
Cyst/o Bladder
Cystitis inflammation of bladder
Cystectomy removal of bladder
Pyel/o Renal collecting duct
Ur/o -uria Urine

3. Hydronephrosis Abnormal condition involving back up of urine into the kidney
Nephrosis A noninflammatory degenerative disease of the renal tubules
Nephrolith A kidney stone.
Urethritis Inflammation of the urethra, the final pathway for urine in both sexes.
Nocturia Frequently getting up and urinating during the night.
Enuresis Involuntary release of urine, most often in reference to "bedwetting.”
Anuria Complete stop of urine flow

4. Dysuria Painful urination
Nocturnal enuresis Bed wetting during sleep
Nocturia Urination at night, not bed wetting
Oliguria Scanty (small) production of urine
Polyuria Condition of excessive urination
Urinepyuria high pus cells in urine
Hydronephrosis Dilation and pooling of urine in the renal pelvis and calyces of one or both kidneys caused by an obstruction of urine flow.

5. Urinary tract infection (UTI)
Invasion of pathogenic organisms (commonly bacteria) in the structures of the urinary tract, especially the urethra and bladder
Symptoms include dysuria, urinary frequency, and malaise

6. Regulation of water and electrolyte balance.
Kidney functions :
Regulation of water and electrolyte balance.
Regulation of acid base balance.
Regulation of arterial blood pressure.
Excretion of metabolic waste products and foreign chemicals.
Hormonal Function : Secretion of erythropoietin

7. Functional units :
The nephron is the functional unit of the kidney . Each kidney contains about one million nephrons.
The nephron is composed of glomerulus and renal tubules .
The nephron performs its function by ultra filtration at glomerulus and secretion and reabsorption at renal tubules.

8. Nephrons and Blood vessels

9. Renal diseases : Many diseases affect renal function.
In some, several functions are affected.
In others, there is selective impairment of glomerular function or one or more tubular function .
Most types of renal diseases cause destruction of complete nephron.

10. Routine kidney function test include the measurement of :
Serum creatinine.
Creatinine clearance.
Serum urea.
Both serum creatinine and creatinine clearance are used as kidney function tests to :
Give an idea about the severity of the disease.
Confirm the diagnosis of renal disease.
Follow up the treatment.

11. Serum creatinine (55-120 mol/L in adult):
Creatinine is the end product of creatine catabolism .
98% of the body creatine is present in the muscles where it functions as store of high energy in the form of creatine phosphate.
Creatinine in the plasma is filtered freely at the glomerulus and secreted by renal tubules (10 % of urinary creatinine).

12. However, creatinine is not reabsorbed by the renal tubules.
Plasma creatinine is an endogenous substance not affected by diet.
Plasma creatinine remains fairly constant throughout adult life.

13. Creatinine clearance :
The glomerular filtration rate (GFR) provides a useful index of the number of functioning glomeruli.
It gives an estimation of the degree of renal impairment by disease.
Creatinine clearance is usually about 110 ml/min in the year old adults.

14. It could be calculated from the following equation:
Clearance is the volume of plasma cleared from the substance excreted in urine per minute.
It could be calculated from the following equation:
  Clearance (ml / min ) = U x V P
U = Concentration of creatinine in urine  mol /l
V = Volume of urine per min
P = Concentration of the substance in serum  mol /l

15. • Serum creatinine is more accurate.
Serum creatinine is a better kidney function test than creatinine clearance because :
• Serum creatinine is more accurate.
• Serum creatinine level is constant
throughout adult life.

16. Creatinine clearance is only recommended in the following conditions:
Patients with early ( minor ) renal disease.
Assessment of possible kidney donors.
Detection of renal toxicity of some nephrotoxic drugs.

17. Serum Urea ( 2.54-6.6 mmol/L) in adult:
Urea is formed in the liver from ammonia released from deamination of amino acids.
As a kidney function test, urea is inferior to serum creatinine because:
High protein diet increases urea formation.
Any condition of increased proteins catabolism will increase urea formation.

18. Dialysis
In medicine, dialysis (from Greek "dialysis", meaning dissolution, "dia", meaning through, and "lysis", meaning loosening) is primarily used to provide an artificial replacement for lost kidney function in people with renal failure.
Dialysis may be used for those with an acute disturbance in kidney function (acute kidney injury, previously acute renal failure) or for those with progressive but chronically worsening kidney function–a state known as chronic kidney disease stage 5 (previously chronic renal failure or end-stage kidney disease).

19. Hemodialysis
In hemodialysis, the patient's blood is then pumped through the blood compartment of a dialyzer, exposing it to a partially permeable membrane.
The dialyzer is composed of thousands of tiny synthetic hollow fibers.
The fiber wall acts as the semipermeable membrane. Blood flows through the fibers, dialysis solution flows around the outside the fibers, and water and wastes move between these two solutions

20. Hemodialysis
The cleansed blood is then returned via the circuit back to the body.
Ultrafiltration occurs by increasing the hydrostatic pressure across the dialyzer membrane. This usually is done by applying a negative pressure to the dialysate compartment of the dialyzer. This pressure gradient causes water and dissolved solutes to move from blood to dialysate, and allows the removal of several litres of excess fluid during a typical 3 to 5 hour treatment.

21. Peritoneal dialysis
In peritoneal dialysis, a sterile solution containing glucose is run through a tube into the peritoneal cavity, the abdominal body cavity around the intestine, where the peritoneal membrane acts as a semipermeable membrane.
The peritoneal membrane or peritoneum is a layer of tissue containing blood vessels that lines and surrounds the peritoneal, or abdominal, cavity and the internal abdominal organs (stomach, spleen, liver, and intestines).

22. Peritoneal dialysis
The dialysate is left there for a period of time to absorb waste products, and then it is drained out through the tube and discarded.
This cycle or "exchange" is normally repeated 4-5 times during the day, (sometimes more often overnight with an automated system).
Ultrafiltration occurs via osmosis; the dialysis solution used contains a high concentration of glucose, and the resulting osmotic pressure causes fluid to move from the blood into the dialysate.

23. Hemofiltration
Hemofiltration is a similar treatment to hemodialysis, but it makes use of a different principle.
The blood is pumped through a dialyzer or "hemofilter" as in dialysis, but no dialysate is used.
A pressure gradient is applied; as a result, water moves across the very permeable membrane rapidly, "dragging" along with it many dissolved substances, importantly ones with large molecular weights, which are cleared less well by hemodialysis.

24. Hemofiltration
Salts and water lost from the blood during this process are replaced with a "substitution fluid" that is infused into the extracorporeal circuit during the treatment.