GFR and ERPF

Question 1

extraction ratio (ER)

Answer 1

fraction of a substance removed from plasma during one circulation through the kidney
- urine elimination and renal retention

Question 2

ER 1 = ?

Answer 2

drug completely removed from circulation in single pass through kidneys

Question 3

ERPF RP agent

Answer 3

MAG3

Question 4

formula for ER

Answer 4

([A]-[V])/[A]
a - arterial conc of substance
v - venous conc of substance

Question 5

UV/P method measures…

Answer 5

renal excretion by measuring amt of substance in urine and the volume of plasma cleared of the substance

Question 6

what is the formula for renal clearance?

Answer 6

(ml/time) = ([Urine] * urine vol/min)/[Plasma]

Question 7

what is the gold standard for GFR?

Answer 7

inulin

Question 8

slope of line D

Answer 8

rate of clearance

Question 9

indications

Answer 9

• serial monitoring of function in renal disease and those undergoing treatment with nephrotoxic drugs
• following post kidney transplant and donation

Question 10

how is camera GFR done?

Answer 10

• syringe counts before injecting patient with camera
• immediately inject and image patient
• post injection syringe counts with camera

Question 11

how far is the syringe usually placed from the camera?

Answer 11

20-30 cm away

Question 12

imaging is done for how long with the gate’s method?

Answer 12

6-30 mins

Question 13

dose when doing camera GFR?

Answer 13

111 MBq DTPA

Question 14

4 GFR blood sampling techniques

Answer 14

1. single sample test
2. two sample test
3. multi sample test
4. multi sample with urine test

Question 15

single sample test

Answer 15

blood drawn 3 hrs post RP
cpm compared to that administered

Question 16

2 sample test

Answer 16

blood drawn at 1 hr and 3 hrs post RP admin

Question 17

multisample test

Answer 17

blood draw at specific intervals

Question 18

which is the most accurate method to determine GFR

Answer 18

multisample test with urine

Question 19

plasma counts high = GFR is ___

Answer 19

low

Question 20

plasma counts low = GFR is ___

Answer 20

high

Question 21

4 broad stages of GFR measurement

Answer 21

1. tracer prep
2. tracer administration
3. blood sampling
4. sample counting

Question 22

dose of RP for blood sampling technique

Answer 22

555 MBq DTPA

Question 23

drawing blood 30 mins too early causes the GFR to be…

Answer 23

falsely low

Question 24

drawing blood 30 mins too late causes the GFR to be…

Answer 24

falsely high

Question 25

normal GFR for men

Question 26

renal plasma flow

Answer 26

amount of plasma arriving for clearance at the glomerulus