renal function tests ppt biochemistry
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RENAL FUNCTION TESTS
Dr Vijay Marakala M.D.
BIOCHEMISTRYSIMS&RC
Formation of urine as the
waste product
Excretion of NPN
substances
Regulation of salt & water
balance
Regulation of acid-base balance
Production of Hormones
Functions of KIDNEY
Assessment of the extent of renal
damage
Monitoring the progression of renal
damage
Monitoring and adjusting the dose of renal toxic drugs
Renal Function Tests –required for……
Renal blood flow
GFR
Renal glomeruli function
Renal tubular function
Urinary output
RFTs give information regarding…….
Classification of RFTs1. Urine analysis
2. Tests for assessment of glomerular function
3. Tests to measure renal plasma flow
4. Tests for assessment of tubular function
1. URINE ANALYSIS
Physical examination
Chemical examination
Microscopic examination
2. Tests for assessment of glomerular function
Renal clearance test
Blood urea and serum
creatinine
Proteinuria Haematuria
RFT
Renal Clearance Test
Renal clearance of a substance is defined as the volume of plasma from which the substance is completely cleared by the kidneys per minute
What is meant by clearance test?
Renal Clearance Test
• Endogenous creatinine and urea• Exogenous inulin
Substances used for clearance test
Renal clearance test used to assess the rate of glomerular filtration and renal blood flow
Creatinine
• Based on the rate of excretion by the kidneys of metabolically produced creatinine
Creatinine clearance test
Creatinine is freely filtered at the
glomerulus and is not reabsorbed by
the tubules
Creatinine
Normal
↓Creatinine clearance
90-120ml/min
↓GFR
Creatinine clearance test
Normal
Sensitivity of the test is
less
75ml/min
40% filtered urea is
reabsorbed
Urea clearance test
Normal
Method of choice for determination
of GFR
120ml/min
Freely filtered & neither reabsorbed
nor secreted by tubules
Inulin clearance test
2. Tests for assessment of glomerular function
Renal clearance test
Blood urea and serum creatinine
Proteinuria Haematuria
RFT
Blood urea and serum creatinine
Blood urea 20-40mg/dl
S. creatinine 0.6-1.2mg/dl
2. Tests for assessment of glomerular function
Renal clearance test
Blood urea and serum
creatinine
Proteinuria Haematuria
RFT
Proteinuria
• Proteinuria in urine is an indicator of leaky glomeruli
• 30-300mg/day is called microalbuminuria• Microalbuminuria is the earliest sign of renal
damage
Small amount of protein usually less than 30mg/day, is found in urine
2. Tests for assessment of glomerular function
Renal clearance test
Blood urea and serum
creatinine
Proteinuria Haematuria
RFT
Haematuria
Intact glomerulus does not allow the passage of RBC.
Glomerular damage, RBC leakage occurs
Tests for Tubular Function
Urine concentration test
Urine dilution test
Specific proteinuria or Tubular proteinuria
Glycosuria
Amino aciduria