indices of thr kidney

Question 1

what does clinical performance of tests include?

Answer 1

Sensitivity - ability to show positive results
Specificity - refers to % of negative results among those that do not have the disease in question
Predictive value - diagnosis and prevalence in population

Question 2

what are specimens commonly analysed?

Answer 2

• whole blood
• serum
• urine
• cerebrospinal fluid

Question 3

what factors can affect test results?

Answer 3

• the way in which the specimen is collected, transported and stored can affect results
• levels of blood constituents can fluctuate throughout the day eg. morning urine samples are best for detecting protein outside normal ranges
• age of patient
• pregnancy
• gender, race, nationality
• physical activity/nutrition

Question 4

what are biochemical test used?

Answer 4

Blood analytes
- urea and electrolytes
- liver function tests
- bone profile
- glucose
- lipids
- endocrinology

Urine analytes

Question 5

what usually follows sodium?

Answer 5

chloride

Question 6

How does sodium move?

Answer 6

moves outside of the cell

Question 7

what are urea and creatinine?

Answer 7

breakdown products

Question 8

at what range would you see glucose in the urine?

Answer 8

above 10mmol/L

Question 9

how is water lost in the body?

Answer 9

through breathing, skin, GI transit

Question 10

how is sodium controlled?

Answer 10

• Renin produced in response to decreased blood flow
• Angiotensin I in lungs converted to angiotensin II by ACE
• stimulates adrenal cortex to produce aldosterone - vasoconstriction
• activates pump in distal renal tubule leading to reabsorption of Na+ and water in exchange for K+ and H+

Question 11

how does a high GFR affect sodium?

Answer 11

high sodium loss

Question 12

how does a high renal tubule blood flow affect sodium?

Answer 12

decreases reabsorption in proximal tubules

Question 13

how is water controlled?

Answer 13

• mainly by sodium conc
• increase in plasma conc causes thirst -> releases ADH from posterior pituitary gland -> increases passive water reabsorption

Question 14

where does ion transport go on?

Answer 14

• acid secretion in stomach
• absorption in GIT
• muscle function; skeletal vs smooth muscle
• neuronal function
• renal-hepatic systems

Question 15

what does low body sodium cause?

Answer 15

cellular over-hydration, confusion, fits

Question 16

what effect does water excess have on the body?

Answer 16

hypertension, cardiac failure, oedema, anorexia, nausea

Question 17

what effect does increased body sodium have on the body?

Answer 17

cellular dehydration, thirst, confusion, coma

Question 18

what are the effects of water deficiency?

Answer 18

hypotension, low pulse volume, decreased skin turgour, tachycardia

Question 19

what is a measure of GFR

Answer 19

creatinine clearance

Question 20

how can creatinine clearance be measured?

Answer 20

collecting urine over 24hrs
take sample for plasma creatinine during 24hrs

Question 21

What is the plasma biochemistry of low gfr (acute renal failure)

Answer 21

Raised: urea, creatinine, K, H, urate, phosphate
Anion gap raised - tells you how much acid is in your blood

Lowered: calcium, bicarbonate

Question 22

what is the plasma biochemistry of tubular dysfunction?

Answer 22

lowered K+, phosphate, urate, bicarbonate
anion gap increased
acidosis
urea and creatinine are normal

Question 23

what is plasma biochemistry of chronic renal failure?

Answer 23

as GFR reduced there is raised creatinine, urea, phsophate, urate
decreased: bicarbonate and Hb
eventually potassium increases and pH decreases

Question 24

what are the classifications of kidney disease?

Answer 24

1 - slight kidney damage with normal or increased filtration
2- mild decrease in kidney function
3- moderate decrease in kidney function
4- severe decrease in kidney function
5- kidney failure