Health   of   any   human   being   is   dependent   on   the   state   of   6   major   organs   in   the body.   They   are   the   brain,   the   heart,   the   lungs,   the   liver,   the   pancreas   and   the kidneys.   Although   there   are   other   organs   that   also   help   maintain   normal health   majority   of   the   problems   are   caused   by   pathology   affecting   one   of   the 6 organs. Important functions performed by the kidney: • Excretion of toxic waste formed in the body • Important in regulating blood pressure • Maintenance of salt and water balance in the body • Role   in   the   synthesis   of   vitamin   D   and   production   of   red   blood   cells (RBC) Kidneys   produce   urine   through   which   most   of   the   waste   products   formed   in   the   body   are   excreted.   If   the   kidneys   malfunction, toxic   waste   products   start   to   accumulate   causing   ill   health. The   kidneys   are   also   responsible   for   maintaining   the   right   amount   of salt   and   water      in   the   body   (electrolyte   balance).   Any   imbalance   in   the   electrolyte   levels   can   again   cause   serious   ill   health ranging from lethargy to unconsciousness and cardiac arrest.   How does the Kidney function: Normally   there   are   2   kidneys   through   which   a   large   volume   of   circulating   blood   flows   through.   The   blood   containing   salts, waste   products   and   all   the   other   components   flow   through   tiny   blood   vessels   bundled   together   in   structures   called   glomerulus. These   are   the   specialised   filtering   units   in   the   kidney.   There   are   approximately   1   million   glomeruli   in   each   kidney.   The   fluid that   is   filtered   from   blood   passes   through   a   series   of   tubules.      As   the   filtrate   flows   through   the   tubules,   all   essential   salts together   with   the   right   amount   of   water   is   reabsorbed   back   in   to   the   circulation.   The   rest   of   the   water   together   with   the   toxic waste products pass through the ureter and stored in the bladder to be excreted later as urine. Urine   is   an   ultrafiltrate   of   blood   plasma.      It   is   slightly   acidic   and   normally   will   not   contain   blood,   protein   or   sugar.   If   any   of these are present it indicates an underlying disease. If   the   glomeruli   or   tubules   are   affected   by   disease,   chemicals   or   poison,   the   kidney   function   will   be   impaired   resulting   in   accumulation   of toxins,   waste   products   and   excess   water.   The   electrolyte   balance   will   also   be   affected.   The   result   is   kidney   failure.   The   grade   of   failure   will depend on the extent of damage. Kidneys Can Be Damaged by: • Environmental Pollutants • Severe Dehydration • Trauma to the Kidney • Myoglobin    released    when    muscles    are    crushed during an accident • Hypertension • Diabetes Mellitus • Cancer • Anti inflammatory Drugs like Ibuprofen • Antibiotics like Gentamycin • Iodine containing medications used in scans. Symptoms of Kidney Failure: • Lethargy • Tiredness • Breathlessness • Loss of appetite • Generalised swelling (oedema) • Puffiness of face • Palpitation • Feeling faint Checking Your Renal Function Renal   or   kidney   function   tests   (RFTs)   are   done   to   assess   how   well   the   kidneys   are   working.   The   tests   are   done   when   there   is suspicion   of   impaired   kidney   function   or   it   is   done   as   part   of   a   routine   health   check.   If   done   as   part   of   a   routine   health   check   a simple blood test alone may suffice. If a thorough investigation is required, urine and blood are both checked. Blood Test The   blood   should   be   checked   for   levels   of   urea,   creatinine,   sugar,   electrolytes   and   glomerular   filtration   rate   (eGFR).   If   any   of the levels are abnormal further assessment should be undertaken. Glomerular   filtration   rate   (GFR)   is   a   measure   of   the   function   of   the   kidneys.   Normal   Glomerular   Filtration   Rate   (eGFR)   is around   90.   This   normally   declines   with   age.   Rates   below   50   indicate   renal   impairment. A   rate   below   15   indicates   severe   renal failure that will require dialysis or kidney transplant to survive. Urine Test Urine   is   usually   tested   for   the   presence   of   blood,   sugar,   proteins   and   signs   of   infection.   Normally   none   of   these   should   be present   in   healthy   individuals.   Albumin,   a   protein   when   present   is   called   albuminuria.   Increased   excretion   of   albumin   would suggest   kidney   damage.   Albumin   Creatinine   Ratio   (ACR)   is   an   important   test   on   the   urine.   Measuring   this   will   indicate   the degree of kidney disease. A   quick   assessment   of   renal   function   can   be   done   by   checking   serum   creatinine,   blood   urea   and   eGFR.   If   any   of   them   are abnormal  more thorough check on kidney function should be undertaken. Other Tests After routine tests if kidney pathology is suspected ultrasound and/or MRI scan may be indicated. Points to Remember: • Kidneys play an important role in maintaining health. • You may be unaware that the kidney is failing until nearly 90% of function is lost • Kidney function may be affected by not drinking enough water • Function may also be affected by routine every day drugs taken for prolonged periods • If you are on any long-term medication, have regular blood test to check Kidney function • High blood pressure is a leading cause of kidney disease. • Diabetes is one of the leading causes of kidney failure. • High cholesterol may indicate risk for heart disease, a major risk factor for kidney disease. • If you are over 60 it is a good idea to have regular health checks that include Renal Function Test. Most   people   with   early   kidney   disease   do   not   have   symptoms.   We   suggest   that   you   have   your   renal   function   tested regularly   if   you   are   over   60   even   if   you   think   you   are   fit.   It   is   particularly   important   if   you   suffer   from   diabetes, hypertension or autoimmune disease. K. Badrinath, FRCS This Topic is discussed in the “Forum” under Nephrology/Urology section