Measurement of Renal Function

Question 1

What does GFR reflect?

Answer 1

Kidney function

Question 2

What is meant by renal plasma clearance of substance?

Answer 2

The amount of blood cleared of a substance per minute.

Question 3

What is the equation for clearance of substance?

Answer 3

CoS = (Urine conc x Urine vol)/(Plamsa conc x time)

Question 4

What substance gives the best result if testing GFR?

Answer 4

Inulin

Question 5

What is commonly used to test GFR?

Answer 5

Creatinine

Question 6

When does CoS = GFR?

Answer 6

1. When it is freely filtered in the glomerulus
2. When it is not secreted or reabsorbed
3. When it isn’t metabolised by the body

Question 7

What is creatinine released by?

Answer 7

Skeletal muscle

Question 8

How is estimated GFR calculated?

Answer 8

eGFR is determined by looking at age, gender, ethnicity, body weight and serum creatinine.

Question 9

When is looking at eGFR not valid?

Answer 9

In cases of sudden changes in kidney function, pregnancy and amputation

Question 10

What is the nephrotic range of proteinuria?

Answer 10

More than 3g of protein excreted a day

Question 11

How can kidney function effect blood pressure?

Answer 11

CKD causes high blood pressure.

High blood pressure worsens CKD.

Question 12

Explain the production and effect of EPO.

Answer 12

1. Hypoxia is detected in the JGA of the kidneys.
2. JGA secrete erythropoeitin.
3. EPO stimulates erythropoeisis in red bone marrow.
4. Erythropoeisis increases RBC count.
5. Blood O2 level returns to normal and EPO production decreases.

Question 13

On average how much urine is produced in 24 hours?

Answer 13

Between 1 and 2 litres

Question 14

EPO is produced where?

Answer 14

The JGA of the kidneys.