Kidney Function Tests

Question 1

What is the gold standard test for measuring GFR?

Answer 1

Inulin clearance

Question 2

Why is inulin clearance the gold standard test for measuring GFR?

Answer 2

It is an exogenous agent which is freely filtered by the glomerulus and is not reabsorbed or secreted by the tubule

Question 3

In addition to inulin, which exogenous agents can be used to measure GFR?

Answer 3

Iohexhol

radiolabelled EDTA

Question 4

What test is done in routine clinical practice to estimate GFR?

Answer 4

Creatinine clearance

Question 5

Other than creatinine, the clearance of which endogenous substance can be used to estimate GFR?

Answer 5

Cystatin C

Question 6

How often is urine collected for the creatinine clearance test?

Answer 6

Every 24 hours

Question 7

Above what level of creatinine clearance is the test no longer accurate?

Answer 7

above 60ml/min

Question 8

How are differences in muscle mass accounted for when estimating GFR from creatinine clearance?

Answer 8

Use of the MDRD formula which has corrective factors for age, sex and ethnicity

Question 9

What is the difference between frank and microscopic haematuria?

Answer 9

This is blood in the urine - frank haemturia is when the blood can be seen with the naked eye whereas in microscopic haemturia blood can only be seen when looking at the sample through a microscope

Question 10

If blood is found in the urine, where might this blood have come form?

Answer 10

Anywhere in the urinary tract from glomerular basement membrane to urethra

Question 11

The ratio of what two substances is used to quantify proteinuria?

Answer 11

Protein:cretainine

Question 12

Protein in the urine indicates damage/a problem with what kidney structure?

Answer 12

Glomeruli

Question 13

Ketones in the urine indicates damage/a problem with what kidney structure?

Answer 13

Tubules

Question 14

What does glucose in the urine indicate?

Answer 14

A problem with or damage to the kidney tubules or an increase in glucose in the blood plasma

Question 15

Abnormal urine pH indicates damage/a problem with what kidney structure?

Answer 15

Tubules

Question 16

If a urine sample appears frothy then what does this indicate?

Answer 16

Presence of protein

Question 17

If a urine sample appearance cloudy then what does this indicate?

Answer 17

Infection

Question 18

What does the presence of nitrites in the urine indicate?

Answer 18

UTI as some bacteria will convert nitrates which are normally present in the urine to nitrites

Question 19

What is the most common cause of glucose in the urine?

Answer 19

Diabetes mellitus