Dr. WASIF ALI KHAN
MD-PATHOLOGY (UNIVERSITY OF BOMBAY)
Assistant Prof. in Pathology
Al Maarefa College
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Serum sodium
136-145 mEq/L, SI-136-145 mmol/L
Critical level--<120 or >160 mEq/L
Serum potassium
Adult: 3.5–5.0 mEq/L: SI units: 3.5–5.0
mmol/L
 Critical Levels: <2.5 or >6.5 mEq/L
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Serum calciumAdult: 8.2 to 10.5 mg/dL; SI units: 2.05–2.54
mmol/L
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Critical levels: >12 mg/dL; SI units: 2.99
mmol/L (coma, death).
<7mg/dL; SI units: 1.75 mmol/L (tetany,
death)
Serum Magnesium1.6–2.2 mg/dL; SI units: 0.66–0.91 mmol/L
 Critical Levels: <1 or >5 mg/dL
Serum Phosphorus Adult: 2.5–4.5 mEq/dL; SI units: 0.78–1.52
mmol/L
 Critical Levels: <1 mg/dL
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Serum ChlorideAdult: 96–106 mEq/L; SI units: 96–106 mmol/L
Critical levels: < 80 mEq/L or >115 mEq/L
Serum BUN
Adult: 10–20 mg/dL; SI units: 3.6–7.1 mmol/L
Critical Levels:
>40 mg/dL (not dehydrated/no history of renal
disease)
>100 mg/dL (patient with history of renal
disease)
>20 mg/dL increase in 24 hr (indicates acute
renal failure)
Serum Creatinine
Adult: Male: 0.6–1.2 mg/dL; SI units: 53–106
mol/L.
Female: 0.5–1.1 mg/dL; SI units: 44–97 mol/L
Serum Uric Acid
 Adult: Male: 4.0–8.5 mg/dL; SI units: 0.24–
0.51 mmol/L.
 Female: 2.8–7.3 mg/dL; SI units: 0.16–0.43
mmol/L
 Critical Levels: > 12 mg/dL
Conventional unit
(mg/day)
SI unit(mmol/day))
Sodium
30-280
30-280
Potassium
40-80
40-80
Chloride
110-250
110-250
Calcium
<275—male
<250--female
<6.8-male
<6.2-female
Magnesium
<150
3-4.3
Phosphorus
0.9-1.3
29-42
RENAL FUNCTION TESTS
1. Routine tests
2. Tests for renal function proper
3. Tests for structural integrity of
kidney
1.ROUTINE TESTS
1. Urine analysis –
2. Blood biochemistry
•Serum creatinine
•Blood urea nitrogen (BUN)
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Serum uric acid
Electrolytes-Na, K, Ca, Ph, Cl
Acid –base analysis-H, HCO3
 Collection
of Urine sample
 Physical Examination
 Chemical Examination
 Microscopic Examination
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Sample should be fresh and examined
immediately ( within 1 hr).
Keeping at room temp
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Reaction changes
Precipitation of crystalline substance
Disintegration of casts
Sample may be contaminated by bacterial growth.
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For routine examination: random sample
Early morning sample (most concentrated) preferred for cellular elements and casts.
Specimen collected 2-3 hrs after a meal for
albumin and sugar
Quantitative studies - 24 hr collection
150 to 200 cc of urine subjected for
examination
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Bacteriological examinations-midstream sample in sterile test tube
-for females, clean perineum and vulva with
soap, water and clean gauze in sequence.
-In males retract the foreskin
For mycobacterial studies - 24 hr specimen is
recommended.
For pregnancy tests- early morning
specimen.
(for 24hr collection)
 Thymol (0.1gm/100ml.)
 Toluol (enough to form a surface film)
 Formaldehyde – for preserving cells and casts
 NaF to inhibit glycolysis
Physical
examination
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Normal adult excretes about 750-2000 ml of
urine per day
Factors affecting volume of urine
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Fluid intake
Diet
Environmental temp.
Humidity
Exercise
Age
Excretion of fluid by respiratory, intestinal tracts
and skin
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Polyuria- diabetes mellitus, diabetes
insipidus,during disappearance of oedema,
chronic nephritis and certain nervous
diseases
Oliguria- (decrease urination) acute and
chronic glomerulonephritis, CCF, shock,
febrile states, dehydration from any cause
Anuria- severe hypotension, acute GN,
crush injuries, mercurial poisoning, after
mismatched transfusion.
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Directly proportional to concentration and
inversely proportional to volume
Normal range 1.003 to 1.030
In diabetes volume as well as specific gravity
is increased
In end stage chronic glomerulonephritis the
specific gravity is fixed at 1.010 despite the
low volume of urine.
Proteinuria also raises the specific gravity
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Normal- pale yellow- urochromes
Alterations
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Yellow green- bile or acriflavin
Red or brown - hemoglobin, beet, aniline
dyes
Smoky red or brown - blood, rhubarb,
senna
Milky - pus, bacteria, fat or chyle
Black - melanin, homogentisic acid,
phenol
Redish purple - porphyrins
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Freshly voided is clear
Cloudiness on standing is due to
-Precipitation of phosphates in neutral/
alkaline urine and urates in acidic urine
Turbidity is due to presence of pus and
epithelial cells, chyle or bacteria
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Normal urine is slightly acidic, pH is 6
Reaction depends on the diet, metabolic state
of the body and micro-organisms in urine.
Reaction is tested by pH papers, litmus paper
and pH meters.
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Normal is aromatic
Ammoniacal odour is due to decomposition
from stasis in the bladder (cystitis)
Fruity odour is due to presence of ketone
bodies seen in diabetes.
Chemical
examination
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Normal urine - 50mg in 24 hrs sample which
is not detected by routine methods
Protienuria - increased glomerular
permeability.
Most commonly filtered is albuminalbuminuria
Abnormal globulins like Bence-Jones proteins
in multiple myeloma
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Diabetes mellitus
Benedicts test
Ketonuria
Diabetic ketoacidosis,
anorexia,
fasting,
Starvation
fever
prolonged vomiting,
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Blood- intact RBC (hematuria) or hemoglobin
(hemoglobinuria)
Benzidine test
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urine→ centrifuge →sediment →mix equal
volume of reagent (saturated benzidine in
glacial acetic acid+ equal quantity of
hydrogen peroxide)
Appearance of blue colour- positive test
Renal diseases
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Acute infections, chronic glomerulonephritis,
tuberculosis of the kidney, nephrotic syndrome,
toxic damage to glomerulus, malignant
hypertension, infarction, renal calculi, trauma to
kidneys, acute cystitis, calculi and tumors in the
ureter or bladder.
Other clinical conditions
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Bleeding disorders such as leukemia,
thrombocytopenia, coagulation factor deficiency,
sickle disease or trait, scurvy.
Use of anticoagulant drugs.
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Hemoglobinuria-the presence of free hemoglobin in the urine as a result
of intravascular hemolysis.
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Hemoglobinuria without hematuria occurs as a result of
hemoglobinemia (i e presence of free hemoglobin in the blood).
The conditions—
1.
Hemolytic anemias autoimmune like G6PD deficiency
2.
Poisoning from snake venom,
3.
4.
5.
spider bites
bacterial toxins like clostridium botulinum
6.
Severe burns
7.
Hemolytic transfusion reactions
8. Sulfonamide and phenacetin administration
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Following are examined under the
microscope after centrifuging
urine at 2000 rpm for 10 min
Cells
Red cells
Epithelial cells
Pus cells
Casts
Hyaline casts
Epithelial casts
Granular casts
Waxy casts
Broad casts
Pus cells
Cylindroids and pseudo casts
Crystals in acidic urine:
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Uric acid
Urates and
calcium oxalates
Crystals in alkaline
urine:
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Triple phosphates
Amorphous
phosphates of calcium
and magnesium
Calcium carbonate
Ammonium biurate
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Cystine
Cholesterol
Leucine
Tyrosine
Sulfonamide
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Look for malignant cells – early diagnosis of
urinary tract malignancies
Fresh urine sample sediment smears stained
by H &E and Papanicolaou stain
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Normal values- male-105+/- 20 ml/min
female-95+/-20 ml/min
Decrease creatinine clearance- significant
reduction of renal function, glomerular
filtration.
Creatinine clearance :
max vol of ml plasma
cleared/minute/standard surface area
= Ucr x V x 1.73/ Pcr x A
Ucr- concentration of creatinine in urine(
mg/dl).
Pcr- Concentration of creatinine in plasma or
serum.
V- Volume of urine flow in ml/minute
A-Body surface area
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Cockcroft-Gault formula
Estimated GFRModification of Diet in renal diseases-MDRD
formula—ser. Creat, age, ethnicity and
gender.
eGFR= 186 x Ser.Creat-1.154 x Age-0.203x
(1.212 if black)x (0.742 if female)
eGFR in mg/dl.
Most diagnostically distinguishing is the
fraction of filtered sodium excreted (FENa).
FENa = Nau x Crs x 100
Nas x Cru
< 1% with adequate tubular function
> 2% with acute tubular necrosis
3.TESTS FOR STRUCTURAL INTEGRITY OF KIDNEY
1. Plain X-ray or KUB
2. IVP
3. Retrograde pyelography
4. Antegrade pyelography
5. Micturating cystourethrogram
6. Renal angiography
7. USG
8. Radio isotope renal scan
9. Renal biopsy.
RENAL BIOPSY:
1. Done when
 Near normal kidney size
 Clear cut diagnosis can not be made by
less invasive measures.
 Reversible disease process can be
clarified.
2. The lesions diagnosed are –
 Glomerulonephritis
 Vasculitis
 H U syndrome
 Allergic nephritis
3. The biopsy specimen is subjected to light
microscopy, immunofluorescence, electron
microscopy
4. Contraindications1. Bilateral small kidney
2. Polycystic kidney
3. Uncontrolled HTN
4. Urinary tract or perinephric infection
5. Bleeding disorder