kidney failure

• Haemodialysis


  • blood from an artery or vein passed into machine that contains an artificial dialysis membrane shaped to form artificial capillaries
  • Heparin added to avoid clotting
  • artificial capillaries surrounded by dialysis fluid, which flows in the opposite direction to the blood (countercurrent)
  • haemodialysis performed at clinic two or three times a week for several hours at each session
• peritoneal dialysis (PD)


  • surgeon implants a permanent tube in the abdomen
  • Dialysis solution poured through the tube and fills space between abdominal wall and organs
  • after several hours, used solution is drained from abdomen
  • PD can be carried out at home or work.
  • dialysis must be combined with carefully monitored diet
  • have to be trained to do this at home
• kidney transplant 


  • while patient is under anaesthesia, surgeon implants new organ into lower abdomen and attaches it to blood supply and bladder.
  • patients given immunosuppressants drugs to help prevent their immune system recognising new organ as a foreign object
• kidney transplant advantages


  • freedom from time - consuming renal dialysis
  • feeling physically fitter
  • improved quality of life - able to travel
  • improved self image - no longer have a feeling of being chronically ill
• kidney transplant disadvantages


  • need to take immunosuppressants
  • need for major surgery under general anaesthetic
  • need for regular checks for signs of rejection
  • side effects of immunosuppressant drugs - fluid retention, high blood pressure, susceptibility to infections
• urine analysis


  • molecules with relative molecular mass of less than 69000 can enter nephron
  • any metabolic product or other substance in blood can be passed into urine if it is small enough
  • if substances not reabsorbed further down nephron, can be detected in urine
• urine can be tested for:

  • glucose in diagnosis of diabetes
  • alcohol to determine blood alcohol levels in drivers
  • many recreational drugs
  • human chorionic gonadotrophin (hCG) in pregnancy testing
  • anabolic steroids, to detect improper use in sporting competitions
• pregnancy testing


  • once human embryo implanted in uterine lining, it produces hormone called human chorionic gonadotrophin (hCG)
  • hCG is a small glycoprotein that can be found in urine as early as 6 days after contraception
  • pregnancy testing kits use monoclonal antibodies which bind to hCG in urine.
• testing for anabolic steroids 1


  • anabolic steroids increase protein synthesis within cells, which results in build up of cell tissue, especially in muscles
  • non medical uses for anabolic steroids controversial because they can give advantage in competitive sports and have dangerous side effects
• testing for anabolic steroids 2


  • all major sporting bodies ban use of anabolic steroids
  • anabolic steroids are small molecules and can enter nephron easily
  • testing for anabolic steroids involves analysing urine sample in laboratory using gas chromatography
• glomerular filtration rate


  the rate at which fluid passes into the nephrons

  • normal reading is in the range 90-120 cm3 min-1
  • figure below 60cm3 min-1 indicates there may be some form of chronic kidney disease
  • figure below 15cm3 min-1 indicates kidney failure and a need for immediate medical attention