This document discusses various biochemical and radiological tests used to evaluate renal function and diagnose renal disease. It describes tests that measure glomerular filtration rate (GFR) like creatinine clearance, urea clearance, and inulin clearance. It also discusses tubular function tests like urine analysis, concentration tests, and acid load tests. Biomarkers of renal injury like kidney injury molecule-1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL), and interleukin-18 are also summarized. Radiological investigations like ultrasound, CT, MRI, renal scans, biopsy and cystoscopy are also mentioned.

1. MAJ R N HOTA
COL MANISH PAUL

2. AIM
To identify renal dysfunction.
To diagnose renal disease.
To monitor disease progress.
To monitor response to treatment.
To assess changes in function that may have
impact on therapy

3. BIOCHEMICAL
RADIOLOGICAL
TISSUE STUDIES
BIOMARKERS

4. Biochemical Tests of Renal Function
Measurement of GFR
• Clearance tests :
• Creatinine clearance
• Urea clearance
• Inulin clearance
• Urea & uric acid
Tubular function tests
• Urine Analysis
• Urine concentration test
• Urine dilution test
• Acid load test
• Phenol – sulphophthalein
test
Serum and Urine
electrolytes
Test to Measure
RPF : PAH Test

5. GFR can be estimated by measuring the urinary excretion of a
substance that is completely filtered from the blood by the
glomeruli and it is not secreted, reabsorbed or metabolized by the
renal tubules.
Clearance : The (hypothetical) quantity of blood or plasma
completely cleared of a substance per unit of time.
Clearance of substances that are filtered exclusively or
predominantly by the glomeruli but neither reabsorbed nor
secreted by other regions of the nephron can be used to measure
GFR.
Measurement of GFR

7. A c u t e K i d n e y i n j u r y n e t w o r k
c l a s s i f i c a t i o n
Stage Serum creatinine (SCr)
criteria
Urine output (UO)
criteria
Stage 1 ≥0.3 mg/dl (26.5 μmol/l) rise or
rise to 1.5–1.99 X baseline
UO <0.5 ml/kg/h for 6 h
Stage 2 Rise to ≥2–2.99 X baseline UO<0.5 ml/kg/h for 12 h
Stage 3 Rise to ≥3 X baseline or ≥4 mg/dl
(354 μmol/l) rise with an acute
rise of at least 0.5 mg/dl (44
μmol/l)
UO<0.3 ml/kg/h for 24 h
or anuria for 12 h

8. 1 to 2% of muscle creatine spontaneously converts to creatinine
daily and released into body fluids at a constant rate.
Depends on : Total muscle mass
Age and sex
Dietary variations
Creatinine released into body fluids at a constant rate and its
plasma levels maintained within narrow limits and hence
Creatinine clearance may be measured as an indicator of GFR.
CREATININE

9. The most frequently used clearance test
Small quantity of creatinine is reabsorbed by the tubules and also are actively
secreted by the renal tubules.
So creatinine clearance is approximately 7% greater than inulin clearance.
The difference is not significant when GFR is normal
but when the GFR is low (less 10 ml/min),
tubular secretion makes the major contribution to creatinine excretion
and the creatinine clearance significantly overestimates the GFR.
CREATININE CLEARANCE

10. An estimate of the GFR can be calculated from the creatinine content of a 24-
hour urine collection, and the plasma concentration within this period.
The volume of urine is measured, urine flow rate is calculated (ml/min)
and the assay for creatinine is performed on plasma and urine to obtain
the concentration in mg per dl or per ml.
•
• CC = Ucr x V(ml/min)
• Pcr
Normal Value ~ 120 ml/min
CREATININE CLEARANCE

11. Cockcroft & Gault Formula
CC = k[(140-Age) x weight(Kg))]
serum Creatinine (µmol/L)
k =1.224 for males
1.04 for females

12. INULIN
GFR =
(U V)
P
inulin
inulin


13. Urea is the major nitrogen containing metabolic product of protein
catabolism in humans.
Its elimination in the urine represents the major route for nitrogen
excretion.
Urea is filtered freely by the glomeruli.
Plasma urea concentration is often used as an index of renal glomerular
function.
Urea production is increased by a high protein intake and it is decreased in
patients with a low protein intake or in patients with liver disease.
Serum Urea

14. Many renal diseases with various glomerular, tubular, interstitial or
vascular damage can cause an increase in plasma urea concentration.
Normal range 5-39 mg/dl.
Plasma concentrations also tend to be slightly higher in males than
females. High protein diet causes significant increases in plasma urea
concentrations and urinary excretion.
Less accurate than Cr
Serum Urea

15. In human, uric acid is the major product of the catabolism of the purine
nucleosides, adenosine and guanosine.
Purines are derived from catabolism of dietary nucleic acid (nucleated cells, like
meat) and from degradation of endogenous nucleic acids.
Overproduction of uric acid may result from increased synthesis of purine
precursors.
In humans, approximately 75% of uric acid excreted via urine.
Hyperuricemia > 7.0 mg/dl in men & >6.0 mg/dl in women
Uric acid

16. Biochemical Tests of Renal Function
Tubular function
tests
Urine Analysis
Urine
concentration test
Urine dilution test
Acid load test
Phenol –
sulphophthalein
test

17. Appearance
Specific
gravity
pH
OsmolalityGlucose
Protein
Urinary
sediments

21. URINE CONCENTRATION TEST
Fluid intake is withheld for 15 hours.
Early morning urine sample is collected. Specific
gravity is measured.
It specific gravity exceeds 1.025, the renal
concentrating ability is considered normal.
If not, indicates renal impairment.

22. Bladder is Emptied.
1,000 to 1,200 ml of water is given to the patient.
Urine sample is collected every hour for the next 4 hours.
Specific gravity is measured
•If the functioning of renal tubule is normal, the urinary specific gravity
should fall to 1.005 or less.
•It the renal tubules are diseased, the concentration of the solutes in
urine will remain constant irrespective of excess water intake.

23. Acid load test is used for the diagnosis of renal
tubular acidosis. Ammonium chloride is administered
orally in a gelatin capsule (0.1g/kg body wt)
Ammonium chloride Dissociates into:
NH4 +(liver) urea &
Cl-(counter balanced by H+) Hcl (urine
acidification)
Urine is collected 2 – 8 hours after ingestion
PH below 5.5 :
Between 5.5 to 7.0 :
Normal
Renal tubular acidosis

24. Non – toxic dye Excreted by kidneys
Intravenous injection of 6mg of PSP is given.
Urine specimen collected at 15,60 and 120 minutes
Rate of excretion of the dye is measured.
15 minutes urine :
1st hour urine :
2nd hour urine :
25% PSP
40 – 60 5 PSP
20 to 25% PSP
Excretion less than 23% in 15 minutes urine sample
indicates impaired Renal excretory function.

25. The major cations in ECF is Na+ > K+ , Mg++, Ca++
The major anions are Cl- and HCO3-
Electrolytes concentration in ECF and ICF can affect:
Metabolic process, osmotic status, hydration and pH
Electrolytes are ions present in body fluids (ECF & ICF)

26. Serum: N.R. 135-153 mEq/L, Urine: N.R. 40-220 mEq/L
Freely filtered than reabsobed (75-90%) by proximal tubulus
Na+ is the major cation in fluid outside of cells and it has an osmotic
activity.

27. Potassium: is the major cation found in ICF (only the 2% is found in
ECF)
 K+ is not reabsorbed by kidney
 K+ serum levels change with pH:
Acidosis
Intracellular Extracellular
K+ H+
Chronic Alkalosis
Associated to K+ decreasing
(ie. Diuretic therapy, vomit, laxatives excess)
Serum: N.R. 3,5-5,3 mEq/L
Urine: N.R. 10-20 mmol/die

28. Para– AminohippurateTest
PAH: Filtered and secreted but Not reabsorbed
PAH clearance is defined as the amount of plasma passed through
kidneys.
Known amount of PAH is injected into the body
Concentrations of PAH in plasma and urine are measured..
RPF = U xV
P
Normal Value 700ml/min

29. BIOCHEMICAL
RADIOLOGICAL
TISSUE STUDIES
BIOMARKERS

30. •X-ray KUB
•Intravenous Pyelogram
•Renal Angiography
•Ultrasound
•CT & MRI
•Renal Nuclear Scans
RADIOLOGY
& IMAGING

31. X-RAY OF KIDNEYS,URETERS AND BLADDER

32. I.V. introduction of a radiopaque contrast medium that
concentrates in the urine and thus facilitates visualization
of the kidneys, ureter, and bladder.
The contrast medium is cleared from the bloodstream by
renal excretion.
Contraindicated in patients with renal failure, uncontrolled
diabetes, multiple myeloma, in patients receiving drug
therapy for chronic bronchitis, emphysema, or asthma.
1
6

34. I.V. catheter is threaded through the femoral and iliac
arteries into the aorta or renal artery.Contrast material is
injected to visualize the renal arterial supply.
Evaluates blood flow dynamics, demonstrates abnormal
vasculature, and differentiates renal cysts from renal
tumors.
May be done to embolize a kidney before nephrectomy for renal
tumor.

36. Uses high-frequency sound waves passed into the body and reflected
back in varying frequencies based on the composition of soft tissues.
Organs in the urinary system create characteristic ultrasonic images
that are electronically processed and displayed as an image.
Abnormalities, such as masses, malformations, or obstructions, can
be identified
Useful in differentiating between solid and fluid-filled masses.
ULTRASOUND

37. 21

38.  In a nuclear medicine renal scan, images, or pictures, are taken of
fluid going into the kidneys through the bloodstream,the filtered wastes
and the flow or drainage of the waste into the bladder.
 A nuclear medicine renal scan uses radioactive medications
injected into a vein, to provide clear images of the kidneys taken with a
gamma camera.
DTPA (diethylene triamine pentaacetic acid)
MAG3 (mercaptoacetyletriglycine)
MAG3 gives clearer images in young children and those patients
with poor kidney function
NUCLEAR MEDICINE RENAL SCAN

39. BIOCHEMICAL
RADIOLOGICAL
TISSUE STUDIES
BIOMARKERS

40. Performed by percutaneous needle biopsy through
renal tissue with ultrasound guidance or by open biopsy
through a small flank incision; useful in securing
specimens for electron and immunofluorescent
microscopy to determine diagnosis, treatment, and
prognosis of renal disease.

41. Cystoscopy is a method of direct
visualization of the urethra and bladder by
means of a cystoscope that is inserted
through the urethra into the bladder. It has a
self-contained optical lens system that
provides a magnified, illuminated view of
the bladder.

42. 24

43. BIOCHEMICAL
RADIOLOGICAL
TISSUE STUDIES
BIOMARKERS

44. BIOMARKERS
A characteristics that is objectively measured and
evaluated as an indicator of normal biological process,
pathogenic process, or pharmacologic response to a
therapeutic intervention”
• —Non – invasive
• —Easily obtainable
• —Measurable using standardized
assays
• —Fast results
• —Incur reasonable cost to perform
—IDEAL
BIOMARKER

45. —> 20 protein biomarkers have been intensively studied.
—Urinary biomarkers are regarded as more non-invasive, easy to
measure, easily obtainable and provide earlier detection of AKI.
—Urinary
Biomarkers
Biomarkers of
structural injury
Biomarkers of
functional injury
Others…

46. B i o m a r k e r s o f s t r u c t u r a l i n j u r y
Type of biomarkers Selective sites and associated types of
injury
Kidney injury molecule-1 (KIM-1) Proximal tubule injury (Ischemic AKI,
nephrotoxins, RCC)
n-acetyl glucosaminadase (NAG) Proximal tubule injury
Neutrophil gelatinase-associated lipocalin
(NGAL)
Tubule and collecting duct injury (Ischem
AKI, nephrotoxins, delay allograft renal
function)
Interleukin (IL)-18 Tubule injury (AKI, delayed allograft ren
function)
Clusterin Tubule injury

47. K i d n e y I n j u r y M o l e c u l e - 1
Trans-membrane receptor of unknown function &
Undetectable in normal kidney tissue or urine.
Markedly increased 1. Ischaemic 2. Nephrotoxic proximal
tubular cell injury 3. Renal cell carcinoma.
Higher urinary KIM-1 associated with worse outcome in
established AKI.
Also predicts graft loss in renal transplant patients.

48. •A Lysosomal enzyme found
abundantly in Proximal
tubular epithelial cells
•Increased urinary
concentrations of tubular
NAG indicates a subclinical
tubular injury
Urinary N
acetyl-β-D-
glucosaminidase
(NAG)

49. • A small 25-KDA polypeptide expressed in distal
tubular cells and collecting ducts
• Undergoes dramatic upregulation after ischemic
tubular injury
• Readily detected in tiny amount (ng/ml) of urine
almost immediately after renal injury
• Precedes appearance of NAG and β2 microglobulin
Neutrophil
Gelatinase
associated
Lipocalin
(NGAL)

50. Most consistent biomarkers found during AKI.
Predominantly found in proliferating nuclear antigen–positive
proximal tubule cells.
Predicts the occurrence of AKI as well as associated morbidity and
mortality patients after cardiac surgery both adults and children.
Available methods…
Urine NGAL
ELISA
Plasma NGAL Kit

51.  Interleukin-18
o Proinflammatory cytokine produced by distal
tubules,collecting ducts of kidney
o Secretion distinctly increases in AKI
o Urinary IL-18 a useful biomarker of AKI
I n t e r l e u k i n ( I L ) - 1 8
Pro-inflammatory cytokine
Mediates inflammatory process (recruits neutrophils)
during ischaemic and septic AKI.
Can predict AKI 1 day ahead of serum creatinine.
Independent predictor of mortality in the patients with
acute respiratory distress syndrome.

52. B i o m a r k e r s o f f u n c t i o n a l i n j u r y
Type of biomarkers Selective sites and associated types of injury
Cystatin C Glomerular injury; in urine indicates proximal
tubule injury
Total protein, β2-microglobulin,
albumin
Glomerular and tubular dysfunction
Carbonic anhydrase Proximal tubule injury
Cathepsin B Proximal tubule injury
β-glucosidase Proximal tubule > distal tubule injury
Lactate dehydrogenase Distal tubule > proximal tubule injury

53. Low MW protein, it is synthesized by nuclear cells,
released in the blood and freely filtered by glomerulus in
urines.
Independent of extrinsic factors: sex, age, diet and
existing infections.
Is a better marker in predicting renal function than
creatinine in patients affected by Chronic Renal
Insufficiency.

54. —Freely filtered at the glomerulus and not secreted in the
tubules
—Predicts the risk of AKI-associated Cardiovascular
morbidity
—Increase urinary cystatin C and alpha 1 - microglobulin
are predictors of an unfavourable outcome in ATN.
—Has higher sensitivity and higher negative predictive
value in determining GFR in CKD.

55. A small protein 11.8KDA component of MHC present on almost all
cells, normally filtered by glomerulus and undergoes partial
tubular reabsorption.
Ratio of β2 microglobulin in serum and urine may help distinguish
Glomerular from Tubular injury.
In tubular Injury reabsorption of β2 microglobulin is impaired, so
urinary levels increase and serum level decrease

56. The plasma concentration of β2-microglobulin is a good index of GFR
in normal people, being unaffected by diet or muscle mass.
It is also increased in certain malignancies and inflammatory diseases.
Since it is normally reabsorbed and catabolized in the tubules,
measurement of β2-microglobulin excretion provides a sensitive
method of assessing tubular integrity.

57. O t h e r s M a r k e r s
Type of biomarkers Selective sites and associated types of
injury
Type IV Collagen Glomerular injury
Liver type fatty acid binding protein (L-
FABP)
Tubular epithelium injury
Alpha-glutathione S-transferase (α-GST) Proximal tubule injury
Tamm-horsfall glycoprotein Distal tubule injury
Brush border antigens
Adenosine deaminase binding protein
Alanine aminopeptidase
γ-glutamyltransferase
α-glutathione-S-transferase
Gamma-glutamyl transferase (γ-GT)
Retinol binding protein 4 (RBP4)
Sodium/hydrogen exchanger isoform
Exosomal fetuin-A

58. THANK
YOU