what are kidney funtion test ? what type of information it gives . how you can evaluate the blood profiles.

1. SUBMITTED TO: Dr. ANAND JAIN SUBMITTED BY: TANVIR SINGH
MVSc. 1st
YEAR
J/V/M/30/2022

2. KIDNEY FUNCTION TESTS
Practical: Renal Function Tests of clinically recovered animals.
Kidney Function Test:- Kidney Function Tests are urine or blood tests that
evaluate how kidneys are working. The kidney plays a major role in regulating the
internal environment of the body. The aim of renal function tests is to detect
impairment of renal function as early as possible. The kidney function can be
assessed by examination of blood and urine.
The functions of kidney include:-
1. Retention of water and electrolytes in a negative energy balance.
2. Elimination of water and electrolytes in a positive body balance.
3. Excretion or retention of hydrogen ions to maintain blood pH.
4. Retention of certain substances such as amino acids, hormones, vitamins,
plasma proteins and glucose.
5. Removal of certain end products such as urea, creatinine and allantoin.
6. Elimination of foreign toxic substances.
7. Production of renin and prostaglandins.
8. Help in activation of Vitamin D.
The following are commonly used kidney function tests:-
(A) Urine examination: Simple routine examination of urine for Volume,
pH, Concentration test / specific gravity test, Osmolality and presence of
certain abnormal constituents (Proteins, ketone bodies, blood, glucose
etc.).
(B) Blood/serum analysis: Estimation of blood urea nitrogen, serum
creatinine, protein and electrolyte.
(C) Glomerular function tests: Clearance test (Urea, inulin, creatinine)

3.  Inulin clearance test: This test is done to find the glomerular sneither
secreted nor absorbed by tubules. Inulin is given subcutaneously or by
intravenous infusion. The amount of inulin excreted in each minutes is
equal to the amount filtered by the glomeruli. Normal rate is 110 to 150
ml per minute.
(D) Tubular function tests: Urine concentration or dilution test, urine
acidification test.
Other important renal function tests:
Estimation and clinical significance of creatinine
Creatinine, in a protein-free filtrate, is determined by its reaction with
alkaline picrate toform a yellow- red tautomer of creatinine picrate, the Jaffc's
reaction. The intensity of the colouris proportional to the optical density which
is measured at 520 nm.
Clinical Significance:
- Clinically insignificant at lower values. It is higher in males since it is
related to body size.
Increased values:
- Increased serum levels are seen in renal failure and other renal
diseases in a mannersimilar to urea.
- Creatinine, however, does not increase with age, dehydration and
catabolic states (eg fever, sepsis, haemorrhage) to the same extent as
urea.
- It is also not affected by diet.
- But the Jaffe's reaction for measuring serum creatinine is not as sensitive
and reliable as method for urea. It is interfered with by Ketone bodies
and glucose and hence false high values may be obtained in diabetes
ketoacidosis.
- serum creatinine is not significant. It is associated with muscle wasting
diseases.
- The creatinine production depends on the modification of the muscular
mass, and it varies little and the levels usually are very stable.

4. ESTIMATION OF BUN (Blood Urea
Nitrogen)
The urea reacts with diacetyl in hot acid solution at nearly 100°C, which is
released from diacetyl monoxime by an oxidative condensation reaction, to
give a coloured product. Diacetyl monoxime is used because of its greater
stability. The absorbance colour developed is measured at 480 nm. The
intensity of the colour developed is proportional to the concentration of urea
present in the sample.
Clinical significance:
The urea concentration varies with the amount of protein in the diet.
Increase of levels: Increases in urea is significant as a measure of renal
function. Increase in blood urea occurs in a number of diseases in addition to
those in which the kidneys are primarilyinvolved. The causes can be classified
as;
Pre Renal: When there is reduced plasma volume it leads to decreased renal
blood flow and hence GFR leading to urea retention. Seen in Reduced plasma
volume:-
- Acute intestinal obstruction – Severe and prolonged vomiting.
- Severe diarrhoea.
- Pyloric stenosis with severe vomiting.
- Ulcerative colitis with severe chloride loss.
- Diabetic Ketoacidosis.
- Shocks, severe burns and haemorrhage.
- Salt and water depletion
- Hematemesis
- In crisis of Addison’s diseases
- Increased protein catabolism:- Fever, Thyrotoxicosis,Cardiac failure -

5. Renal Disease: Blood urea is increased in all forms of renal diseases like;
- Acute glomerulonephritis.
- Renal failure
- Malignant hypertension
- Malignant nephrosclerosis
- Hydronephrosis
- Chronic pyelonephritis
- Congenital cystic kidneys
Post renal: Due to obstruction to flow of urine there is retention and so
reduction in effective filteration pressure at the glomeruli; when prolonged
produces irreversible kidney damage. Causes are:
- Enlargement of prostrate.
- Stones in urinary tract.
- Stricture of the urethra
- Tumors of the bladder affecting urinary flow
Decreased levels: It is rare but may be seen: In some cases of severe liver
damage. Physiological condition- Blood urea has been seen to be lower in
pregnancy than in normal non pregnant.
Water Deprivation Test (Abrupt)
In non azotemic patients, the test is useful to evaluate renal functions. I dehydrated
animals, if the urine is not concentrated the animal has failed the test and further
water deprivation could be highly dangerous.
1. After emptying the bladder using catheter, weigh the animal.
2. Withhold water. Give dry food if test continues more than 24 hours.
3. Measure body weight, total plasma proteins, packed cell volume, serum
osmolality and skin turgor every 2 to 4 hours. This helps to monitor dehydration.
4. Measure urine specific gravity, urine osmolality and urine/plasma osmolality.

6. ratio every 2 to 4 hours. This helps to monitor urinary concentrating ability
5. This test is continued until patient becomes dehydrated or urine is concentrated.
There is loss of 5 per cent or more of its body weight.
6. Increase in urine osmolality (<5%) or change in specific gravity (<10%) for three
consecutive determinations or the animal loses 5% of its body weight, the animal
may be given vasopressin (0.25 to 0.5 U/kg, maximum dose SU) or desmopressin
(1 ug/kg) sub-cutaneously. Measure the parameters of urinary concentrating ability
after 1 to 2 hours of antidiuretic hormone injection.
In healthy dogs, the urine specific gravity reaches 1.050 to 1.076 after water
deprivation. This is sufficient to cause dehydration. The expected urine osmolality
is 1787 to 2791 mOsm/kg and osmolality ratios of their urine/plasma is 5.7 to 8.9.
Water Deprivation Test (Gradual)
In this test, owner of the dog is advised to reduce water consumption by 20 per cent
for 3 to 5 days but not less than 60 ml/kg/day. Provide dry food ad-libitum o
during this period. Proceed for abrupt water deprivation test as described earlier at
the end of 3 to 5 days.
Antidiuretic Hormone Test
This test is performed when patients cannot concentrate urine after water
deprivation or in patients in which water deprivation is risky.
1. Inject intramuscularly 3 to 5 U of vasopressin tannate in oil.
2. Provide water ad-libitum and empty bladder every 3 to 6 hours after injection.
Measure specific gravity of urine at 0, 6, 12, 18 and 24 hours.
In healthy dogs, a maximal urine specific gravity of 1.024 to 1.060 at 8 hours is
expected. The maximal urine osmolality should be 1033 to 2001 mOsm/kg while
maximal urine/plasma osmolality ratio should be 3.8 to 7.4.

7. REFERENCE VALUES FOR SERUM CHEMISTRY FOR ANIMALS
OF DIFFERENT SPECIES
Component Units Canine Feline Equine Bovine Porcine Ovine
Albumin g/dl 2.5-3.6 2.3-3.4 2.7-4.2 2.7-4.3 1.9-3.3 2.4-3.9
Bilirubin
(total)
mg/dl 0.1-0.3 0.1-0.2 0.5-2.1 0.1-0.3 0.1-0.2 0.1-0.4
Calcium mg/dl 9.0-10.8 7.4-
10.5
10.6-
13.0
7.9-10.0 8.0-12.0 10.4-
13.0
Cliloride mEq/
L
110-118 116-
125
97-104 94-104 100-105 98-115
Cholesterol mg/dl 108-266 38-186 50-143 87-254 36-54 50-140
Creatinine mg/dl 0.5-1.4 0.7-1.8 1.0-1.9 0.7-1.1 1.0-2.7 1.2-1.9
Globulin g/dl 2.4-4.0 2.6-4.5 2.1-3.8 2.5-4.1 5.3-6.4 3.5-5.7
Glucose mg/dl 77-120 58-120 76-127 37-71 65-95 50-80
Hemoglobin g/L 130-190 90-150 110-170 80-150 100-180 80-160
Magnesium mg/dl 1.8-2.4 2.0-2.2 2.2-2.8 1.8-2.3 2.7-3.7 2.2-2.8
Phosphorous
(inorganic)
mg/dl 2.4-6.1 2.6-7.9 2.0-4.3 4.6-9.0 5.3-9.6 5.0-7.3
Potassium ppm 4.2-5.6 4.0-5.3 2.4-5.2 4.0-5.3 4.9-7.1 4.0-6.0
Protein (total) g/dl 5.4-7.1 5.7-7.9 5.5-7.3 5.9-7.7 7.0-8.9 6.0-7.9
Sodium ppm 145-153 151-
158
136-142 136-144 139-152 136-154
Blood Urea
Nitrogen
mg/dl 7-25 18-33 12-26 10-26 8-24 18-31