Renal Function Tests

Question 1

Important renal function tests with normal values

Answer 1

1. Routine Examination of Urine

A. Physical Examination

Quantity

Colour

Odour

Appearance

Sedimentation

Specific gravity

B. Chemical Examination

Reaction (pH) – Litmus paper test

Albumin – Heat coagulation test

Sugar – Benedict test

Excess phosphate

Bile salts – Hay’s surface tension test

Bile pigment (bilirubin) – Fouchet test

Ketone bodies – Rothera’s test

Urobilinogen

Bence-Jones protein

C. Microscopic Examination

Cells

RBC

Pus cells

Epithelial cells

Casts

RBC casts

WBC casts

Epithelial casts

Granular casts

Hyaline casts

Crystals & Others

Urates

Uric acid

Calcium oxalate

Amorphous phosphate

Triple phosphate

2. Blood Analysis

Blood urea

Serum creatinine

Serum electrolytes

3. Renal Clearance Tests

Creatinine clearance test

Urea clearance test

Inulin clearance test

4. Imaging Tests

Plain X-ray KUB

Ultrasonography (USG)

Intravenous urography (IVU)

CT scan

MRI

5. Radionuclide Study

Renography

Pg 850

Question 2

Causes of uremia

Answer 2

Pg 857

Question 3

Clinical importance of serum uric acid

Answer 3

1. AGN
2. Nephrotic syndrome
3. Acute renal failure
4. Chronic renal failure
5. Urinary tract obstruction
6. Gout
7. Polycythemia vera
8. Chronic lymphocytic leukemia
9. Lymphoma
10. Eclampsia

Question 4

Why is serum creatinine level more specific

Answer 4

Serum creatinine is more specific because it is produced from muscle at a constant rate and is almost completely filtered at the glomerulus. If muscle mass remains constant, changes in creatinine concentration reflect changes in GFR.

Blood urea is a poor guide to renal excretory function as it varies with protein intake, liver metabolic capacoty and renal perfusion.

Question 5

Massive proteinuria definition

Answer 5

When more than 3.5 gm albumin passes through urine in 24 hrs

Question 6

Causes/diseases associated with massive proteinuria

Answer 6

1. Nephrotic syndrome
2. Toxemia of pregnancy
3. Diabetic nephropathy
4. Lupus nephritis
5. Amyloidosis
6. Multiple myeloma

Question 7

Bence Jones protein

Answer 7

Pg 862

Question 8

Reducing agents found in urine

Answer 8

1. Sugar substances: Glucose, lactose, pentose, fructose & galactose
2. Non-sugar substances: Homogentisic acid, nalidixic acid, drugs (cephalosporin, ascorbic acid or aspirin)

Question 9

Benedicts test

Answer 9

Pg 863

Question 10

Causes of hematuria

Answer 10

Pg 866

Question 11

Urinary findings in nephrotic syndrome

Answer 11

Pg 868