The document discusses renal function tests, emphasizing the kidneys' role in waste excretion and homeostasis. It outlines various clinical tests for evaluating kidney function, including glomerular filtration rate, proteinuria, and tubular function, as well as the significance of serum and urine parameters. Additionally, it mentions the importance of renal biopsy in diagnosing and managing kidney diseases.

1. Renal FunctionTests
Presented by-Asma Fatima,
Pharm.D
Sultan-ul-Uloom College of Pharmacy,
Hyderabad.
GUIDED BY
Dr. S P SRINIVAS
NAYAK.
Assistant Professor,
SUCP, HYD.

2. -Kidneys play a vital role in the excretion
of waste products and toxins from blood
such as urea, creatinine and uric acid and
maintain the acid-base balance and the
overall homeostatic mechanism of the
body.
-They are several clinical laboratory tests
that are useful in investigating and
evaluating kidney function.
RENAL FUNCTIONTESTS (RFT)
1. GLOMERULAR FUNCTION 5. SERUM
PARAMETERS
- Clearance test - urea
- creatinine
2.GLOMERULAR PERMIABILITY - Na electrolyte
-Proteinuria - K+ electrolyte
3. TUBULAR FUNCTIONS 6. URINE ANALYSIS
-physical, chemical or
microscopic
examination
4. RENAL PLASMA FLOW 7. RENAL BIOPSY
- Para amino hippurate test

3. 1. Glomerular Filtration
-clearance test
GLOMERULAR FILTRATION-
Glomerular filtration rate (GFR) is a test used to check how well the kidneys are
working. Specifically, it estimates how much blood passes through
the glomeruli each minute to get purified.
According to the National Kidney Foundation, normal results range from 90 to 120
mL/min

4. CLEARANCE-"Amountof plasmaor bloodcompletelyclearedof somesubstanceinunittime"
Aspecificsubstanceclearanceisusuallyevaluatedto getthe estimatedGFRlevels.Someof the substancesare-
INULIN
• Completely filtered
• No reabsorbtion by
renal tubules
• No tubular secretion
• Clearance = 100%
• But not used
practically due to I.V
adm
CREATININE
• Completely filtered
• No absorbtion by
renal tubules
• Tubular secretion
occurs
• Clearance = more
• Normal values are:
Male: 97 to 137 mL/min
• Female: 88 to 128
mL/min
BUN
• Completely filtered
• 40% absorption
occurs by the tubules
• No tubular secretion
• Clearance= less
Adult 6-20 mg/dL
>60 years 8-23 mg/dL
Cimitidine and trimethoprim decreases tubular secretion of creatinine therefore values near GFR
are obtained.

5.  The most popular formula is that of Cockcroft and Gault:
 GFR = [140–age (y)] × weight (kg)/serum creatinine (µmol/L)] × 1.23 - MALE
 GFR = [140–age (y)] × weight (kg)/serum creatinine (µmol/L)] × 1.04 - FEMALE
Creatinine
– AKI and CKD
BUN
Creatinine- low muscle mass
BUN- liver failure, ammonia is not
converted to urea and causes
hepatic encephalopathy,
Malnutrition
BUN/CREATININE RATIO
Heart failure, blood loss, salt
depletion, GI bleeding
Severe liver disease,
rhabdomyolosis,SIADH

6. 2. GLOMERULAR PERMIABILITY
- PROTEINURIA
It may result due to
glomerular permeability
reabsorption of filtered protein
excretion of tubular enzymes.
Proteinuria is one of the most potent risk markers for progressive loss of renal function
in renal disease, e.g. diabetic nephropathy, chronic glomerulonephritis and reflux
nephropathy. In addition, treatments that reduce proteinuria (e.g. antihypertensive
drugs, particularly ACE inhibitors) decrease rate of progression.
Gold standard’ is 24h urine collection for measurement of total protein or albumin.
Proteinuria >300mg/24h is usually defined as pathological, but patients with early
diabetic nephropathy have total protein excretions below this limit. Only when
proteinuria >1g/24h is there a high suspicion of underlying renal disease.

7. ANOTHER SCREENING TEST FOR
PROTEINURIA
URINE DIPSTICK TEST-
A urine dipstick test is the quickest way
to test urine. It involves dipping a specially
treated paper strip into a sample of your urine
-The strip has squares on it that change colour
in the presence of certain substances.The
strip will then be compared to a chart on the
side of the urine testing strip package. Often
the more intense the colour change, the more
of the substance there is in the urine.

8. 3. TUBULAR FUNCTION
1.Screening tests for generalised tubular dysfunction test
for Renal glycosuria (dipstick or lab test for glucose in urine plus
normal plasma glucose).
2 Hypophosphataemia (can be followed by estimation of
phosphate reabsorption
3.Low molecular weight proteinuria (due to failure of tubular
reabsorption plus increased release of proteins derived from
tubular cells)

9. 4. RENAL PLASMA FLOW
- para amino hippurate test
Renal plasma flow is the volume of plasma that reaches the kidneys per
unit time
PAH (para-aminohippurate) is freely filtered, is not reabsorbed, and is
secreted within the nephron. In other words, not all PAH crosses into the
primary filtrate in Bowman's capsule and the remaining PAH in the vasa
recta or peritubular capillaries is taken up and secreted by epithelial
cells of the proximal convoluted tubule into the tubule lumen. In this way
PAH, at low doses, is almost completely cleared from the blood during a
single pass through the kidney.

10. 4.SERUM PARAMETERS
Na+ ( sodium electrolyte )
24h urine sodium is usually measured on a sample collected in a plain container.
However, it can also be measured, by flame photometry
Fractional excretion of sodium is calculated as
{(urine [sodium] × plasma [creatinine])/plasma [sodium] × urine
[creatinine])} × 100%
Hypernatremia means you have high levels of sodium in your blood.
k+ ( potassium electrolyte )
Normal (adults): 25–125 millimoles (mmol) per day (24 hours)
Normal (children): 10–60 mmol per day (24 hours)

11.  Low urinary K+ (<20mmol/L) with hypokalemia is seen in
Gastrointestinal potassium loss, e.g. diarrheoa, laxative abuse. 2
Dietary deficiency. 3.Skin losses, e.g. burns, severe eczema.
 High urinary K+ (>20mmol/L) with hypokalemia is seen in
 1. Diuretic use, abuse and conditions which mimic diuretic use, e.g.
Bartter’s syndrome.
 2.Tubular damage causing potassium wasting, e.g. renal tubular
acidosis types 1 and 2.
 3. Diabetic ketoacidosis.

13. 6.URINEANALYSIS

15. 7.RENAL BIOPSY
Renal biopsy Percutaneous renal biopsy is a valuable tool to establish
diagnosis and guide therapy in renal diseases. It also has a major role in the
management of a renal transplant recipient.
Definite indications
Nephrotic syndrome (in adults).
Rapidly progressive glomerulonephritis.
Unexplained renal failure with normal-sized kidneys relative to body size and
age.
Relative indications (result may change management or help to define
prognosis)
Non-nephrotic range proteinuria with or without haematuria.
Unexplained chronic renal failure.
Absolute contraindications
Uncontrolled severe hypertension, Bleeding.

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