5. RATE OF URINARY EXCRETION OF
ANY SOLUTE
= RATE OF GLOMERULAR FILTRATION
+ RATE OF SECRETION
- RATE OF REABSORPTION
6.
7. PHYSICAL TESTS
i. URINE VOLUME
Assessment of fluid balance and kidney
function.
Normal value;
adult : 800-2500 mL/day
children : 500-1400 mL/day
8. CLINICAL IMPLICATIONS
1. polyuria with elevated BUN and creatinine .
diabetic ketoacidosis
partial obstruction of urinary tract
tubular necrosis
2.polyuria with normal BUN and creatinine.
diabetes mellitus and diabetes
insipidus
tumours of brain and spinal cord
9. 3.oliguria
Renal causes
renal ischemia
renal disease due to toxic agents
Dehydration caused by prolonged
vomiting,diarrhoea,burns
Obstruction of some area of the urinary tract
Cardiac insufficiency
4.anuria
Complete urinary tract obstruction
Acute cortical necrosis
Glomerulonephritis
Acute tubular necrosis
11. 2.URINE COLOUR
Yellow colour due to urochrome.
Normal;
Pale yellow to amber
Straw colour- low SG
Amber colour-high SG
12. CLINICAL IMPLICATIONS
Almost colourless urine;
large fluid intake
chronic interstitial nephritis
untreated diabetes mellitus
diabetes insipidus
alcohol and caffeine ingestion
diuretic therapy
nervousness
Orange colour;
fever
carrots or vitamin A
phenazopyridine, nitrofurantoin
13. Green urine;
pseudomonal infection
chlorophyll
Red urine
RBCs
haemoglobin
myoglobin
porphyrins
Black urine
melanin
phenol poisoning
Smoky urine - RBCs
Milky urine - fat,cystinuria,WBCs
14. INTERFERING FACTORS
Colour darkens on standing
Drugs alter the colour
green - indomethacin
brown - chloroquine,furazolidone
pink to brown - laxatives
red-pink - daunorubicin
orange - rifampicin
blue urine - triamterene
black urine - chloroquine
metronidazole
15. 3.URINE ODOUR
Faint odour owing to the presence of
volatile oils.
normal; aromatic odour.
16. CLINICAL IMPLICATIONS
Diabetes mellitus patients urine have a
fruity odour.
UTIs result in foul-smelling urine .
Infants with a inherited disorder of amino
acid metabolism urine smells like burnt
sugar.
Cystinuria result in sulfurous odour.
17. 4.URINE SPECIFIC GRAVITY
(SG)
Measurement of the kidneys ability to
concentrate urine.
Compares the density of urine against
the density of distilled water.
Normal;
1.005-1.030
23. CHEMICAL EXAMINATION OF
URINE
ENDOGENOUS MARKERS
a) SERUM CREATININE (kreas)
breakdown product of muscle creatine phosphate.
excreted by glomerular filtration and tubular
secretion.
doubles with each 50% decrease in GFR.
if SCr is 1mg/dl, 100% renal function
2mg/dl, 50% renal function
24. Normal;
URINE CREATININE
men : 14-26mg/kg/24 hours
women: 11-20mg/kg/24 hours
SERUM CREATININE
men : 0.6-1.2 mg/dL
women : o.4-1.0 mg/dL
28. URINE CREATININE
INCREASED BY DECREASED BY
Ascorbic acid Anabolic steroids
Corticosteroids Captopril
Methotrexate Thiazides
Methyldopa Ketoprofen
Cefoxitin
29. CREATININE CLEARANCE
Rate at which creatinine is removed from
the blood.
Useful measure of
glomerular filtration rate
excreting capacity of the kidney.
31. SCHWARTZ FORMULA
crcl(ml/min) = k x ht in cm/scr(mg/dl)
k = 0.45 ,infants < 1 year of age
k = 0.55 ,children and adolescent
females.
k = 0.7, adolescent males.
33. CLINICAL IMPLICATIONS
INCREASED
State of high cardiac output
pregnancy
burns
carbon monoxide poisoning
DECREASED
Impaired kidney function
dehydration
hemorrhage
congestive heart failure
34. INTERFERING FACTORS
Exercise may increase creatinine
clearance and urine creatinine.
Pregnancy increases CrCl
Proteinuria and advanced renal failure
make CrCl an unreliable method for
determining GFR.
35. BLOOD UREA NITROGEN
End product of protein metabolism (liver)
It travels through the blood and is
excreted by the kidney.
BUN measures the amount of nitrogen in
the blood in the form of urea.
36. Normal value;
Adults : 6-20 mg/dl
Elderly patients : 8-23 mg/dl
Children : 5-18 mg/dl
AZOTEMIA; excessive retention of nitrogenous
waste products.
Renal azotemia ; renal disease (glomerulonephritis
and chronic pyelonephritis).
Prerenal azotemia; severe dehydration
hemorrhagic shock
excessive protein intake.
Postrenal azotemia; urethral stones
tumours
prostatic obstructions.
37. CLINICAL IMPLICATIONS
1.Increased BUN levels (azotemia)
a.impaired renal function
congestive heart failure
salt and water depletion
stress
acute MI
b. chronic renal diseases
c. Urinary tract obstruction
d. hemorrhage into GI tract.
e. diabetes mellitus
2. Decreased BUN levels
a. liver failure
b. acromegaly
c. malnutrition
39. ACE inhibitors
Indomethacin
Penicillin
Thiazides
Rifampin
Spironolactone
Timolol
Cefotaxime
Phenothiazines
Chloramphenicol
Levodopa
Amikacin
• BUN increased by BUN decreased by
40. GLOMERULAR FILTRATION RATE
GFR is the volume of water filtered or
cleared out of the plasma per minute.
GFR is approximated by measuring
the urinary excretion rate of a marker
substance.
Example for marker inulin.
42. URINE PROTEINS
Increased amounts of protein is an
important indicator of renal diseases.
Normal value;
Adult male:10-140 mg/dl
Female:30-100 mg/dl
55. URINE CHLORIDE
Diagnose dehydration or as a guide in
adjusting fluid and electrolyte balance.
Also useful in monitoring the effects of
reduced salt diets( CVD,HTN)
Normal value;
adult: 140-250 mEq/24 hours
child : 64-176 mEq/24 hours
57. URINE CHLORIDE
Ammonium chloride
administration
Excessive infusion of
normal saline
Ingestion of sulfides,
cyanides, halogens,
bromides and sulfhydril
compounds.
Carbenicillin therapy
Reduced dietary
intake of chloride
Ingestion of large
amounts of licorice
Alkali ingestion
Dehydration
INCREASED
CHLORIDE
DECREASED
CHLORIDE
58. URINE KETONES
From fatty acid and fat.
Consists mainly of three substances
: acetone,
β-hydroxybutyric acid
acetoacetic acid.
normal value;
urine: negative (<0.3 mg/dl)
59. CLINICAL IMPLICATIONS
Hyperthyroidism
Fever
Pregnancy or
lactation
Diabetes mellitus
Starvation
Anorexia
INCREASED
METABOLIC STATES
DECREASED
METABOLIC STATES
60. KETONES IN URINE
Amino salicylic acid
Cefixime
Valproic acid
Dimercaprol
Captopril
Aspirin
Phenazopyridine
INCREASED BY DECREASED BY
61. MACROSCOPIC EXAMINATION
of centrifuged urine.
1) Hematuria
it indicates trauma, tumour, systemic
bleeding.
2) casts
Casts are cylindrical elements with
parallel sides
67. EXOGENOUS MARKERS
INULIN CLEARANCE
normal value;
men : 127ml/min/m²
women: 118ml/min/m²
Fructose polysaccharide.
Patient receives inulin to achieve a steady
blood concentration.
The quantity in plasma and the amount
excreted in urine is measured.
68. IOTHALAMATE
Normal value;
men : 127 ml/min/m²
women: 118 ml/min/m²
Injection of the radioactive exogenous
marker .
These are not widely used.
69. REFERENCES
A manual of laboratory and diagnostic
tests; by Frances Fischbach, Marshall
B.Dunning, Edition 8.
Textbook of therapeutics; Drug and
disease management by
Eric.T.Herfindal,sixth edition.
Comprehensive pharmacy review by
Leon shargel,fourth edition.
Basic skills in interpreting laboratory
data by Mary Lee,fourth edition.
Principles of anaatomy and physiology
by Tortora, tenth edition.