labs

Question 1

produced as the result of normal muscle metabolism? what is the breakdown from?

Answer 1

creatinine– production & excretion are constant/regular
breakdown of phosphocreatine

Question 2

used to approximate the GFR? what is the normal level

Answer 2

creatinine– normal is 0.5-1.5 mg/dL

Question 3

relationship between GFR & serum creatinine

Answer 3

inverse! 2x increase in Cr= 50% decrease in GFR so mild elevation= significant dysfunction even if its in the normal range

Question 4

what is CrCl

Answer 4

• measure of the GFR
• normal is 100ml/min; dependent on age and gender (m>f)

Question 5

how is CrCl measured directly?

Answer 5

24 hour urine collection– time consuming & hard for patients; both serum & urine needed; dispose of the first urine
- does NOT give a more accurate estimate than the prediction equations

Question 6

how is CrCl measured indirectly

Answer 6

cockcroft-gault equation– age, kg, sex & serum cr are used in it
- used as the standard for drug dosing

Question 7

sum filtraion of all functioning nephrons; gold standard for measuring kidney function? what is normal value?

Answer 7

GFR– varies by age, gender & body size
normal is above 90

Question 8

5 uses of GFR

Answer 8

• identify kidney dz
• select doses
• avoid certain meds
• monitor CKD
• criteria for referral & dialysis

Question 9

produced in liver, found in blood & secreted and reabsorbed by the kidneys; directly related to metabolic liver function; assuming normal liver, it is estimate of renal function

Answer 9

BUN– also affected by protein breakdown, hydration status, liver failure; rises faster than Cr with dehydration

Question 10

how does serum Cr, eGFR, CrCl, BUN change when kidney is going bad?

Answer 10

Decreases– eGFR & CrCl
increase– serum Cr, BUN

Question 11

symptomatic azotemia– N/V, lethargy

Answer 11

uremia

Question 12

what is the diff. btwn acute and chronic kidney failure

Answer 12

time— 3 months

Question 13

good screening test for obstruction & differentiation btwn acute & chronic renal dz

Answer 13

renal US

Question 14

size difference btwn small & large kidneys

Answer 14

small < 10 cm; chronic dz
large > 12 cm; acute (potentially reversible; associated w/ DM, amyloid, infiltrative CA)

Question 15

5 tests that can help in finding the cause of kidney failure

Answer 15

BUN:Cr
Urine NA
fractional excretion Na
urine Sp Gr
urine osmolality

Question 16

in presence of kidney disease, what does BUN/Cr of over 20 mean?

Answer 16

pre-renal: GI bleed, less volume
Urine obstruction

Question 17

in presence of kidney disease, what does BUN/Cr of under 20 mean?

Answer 17

intrarenal
often Chronic (CKD)

Question 18

random urine Na of what value suggests dehydration? what value sugguests kidney/adrenal disease?

Answer 18

• Na under 10 suggests dehydration– CHF, liver dz
• Na over 20 suggests kidney/adrenal dsease
• electrolytes can be used to calculate FENa

Question 19

helpful to distinguish btwn pre-renal and intrarenal azotemia; over 1% means intra-renal azotemia while under 1% means pre-renal azotemia

Answer 19

FENa (fractional excretion of Na)

Question 20

prerenal vs intrarenal vs postrenal

• urine Na under 10
• serum BUN:Cr over 20
• FENa under 1%
• Sp Gr over 1.020
• U osmolality over 500

Answer 20

prerenal

Question 21

prerenal vs intrarenal vs postrenal

• urine Na over 20
• serum BUN:Cr under 10
• FENa over 1%
• Sp Gr under 1.012
• U osmolality under 250

Answer 21

intra-renal

Question 22

what GFR is considered moderate CKD3 & signals need to refer?

Answer 22

30-59

Question 23

what GFR signals dialysis?

Answer 23

under 15

Question 24

this measurement is determined by # and size of particles in the urine & varies with osmolality. what is the normal range for this lab value?

Answer 24

Specific gravity
normal is 1.005 to 1.025

osmolality is more accurate & is determined by # of particles only

Question 25

what is the normal pH range for urine?

Answer 25

4.5 to 8.0; usually 6.0

Question 26

uncontrolled DM, starvation, dehydration, protein changes your urine pH in what way?

Answer 26

makes it acidic

Question 27

chronic renal failure, salicylate intox., proteus infection changes your urine pH how?

Answer 27

makes it alkaline

Question 28

persistent proteinuria is classified into what 3 ways?

Answer 28

glomerular tubular overflow

Question 29

# what class of persistent proteinuria is this - may cause massive proteinuria & has many causes - albumin is primary protein

Answer 29

glomerular

Question 30

# what type of persistent proteinuria - malfunctioning tubule cells don't metabolize or reabsorb normally filtered protein - LMW proteins predominate - rarely exceed 2g/day

Answer 30

tubular

Question 31

# what type of persistent proteinuria - LMW proteins overwhelm ability of tubules to reabsorb filtered proteins - can be seen in multiple myeloma?

Answer 31

overflow

Question 32

what do you do if there is mild proteinuria on dip in an asymptomatic patient

Answer 32

recheck the dipstick it can be transietnt d/t many things

Question 33

4 things to do if there is proteinuria in a non-asymptomatic patient

Answer 33

- get 24hr urine - microscopic exam of urinary sediment - urinary protein electrophoresis - assess renal function

Question 34

you get a 24 h urine test and the value is **under 3g/24hrs** what type of disease is this? **over 3g/24hrs**?

Answer 34

- under 3g: glomerular or tubular disease (nephritic)-- could be either but tends to be tubular - **over 3g**: nephrotic range, typically **glomerular**

Question 35

# what is this called? excretion of **30-150mg of protein/day** found via other test (not dipstick); affected by hydration status and **indicates renal tubular disease**

Answer 35

microalbuminuria - if patient has this + DM, should start ACEi

Question 36

if patient has glucosuria but not DM after checking for it, what is likely happening?

Answer 36

its renal **tubular** disease

Question 37

other than diabetes & diets, what are 3 other times you may expect to see ketones in urine

Answer 37

- strenuous exercise - frequent vomiting - pregnancy

Question 38

bilirubin vs urobilinogen-- which is normally found in urine in small amounts?

Answer 38

urobilinogen

Question 39

if someone has microscopic hematuria w/o e/o renal dz, what do we do? why?

Answer 39

recheck it in weeks & if still present, refer to urology because it can be serious urologic disease or malignancy

Question 40

transitional epithelial cells means what?

Answer 40

can be normal but if in large amounts may suggest a UTI

Question 41

which type of cells seen in microscopic UA is the desquamation of tubular epithelium that suggests significant renal pathology

Answer 41

tubular epithelial cells

Question 42

over ____ is significant bacteriuia in asymp. pt while over ____ suggests UTI in pt w/ sx. what should you do after diagnosing bacteriuria?

Answer 42

- over 100K mL in asymptomatic = significant bacteriuria - over 100 mL in sx suggests UTI - after dx, need C & S (culture and sensitivity)

Question 43

# what type of cast? * small # w/ exercise, dehydration, stress, pyelonephritis but may be normal * from distal tubules * protein w/o cellular inclusion

Answer 43

hyaline cast

Question 44

# what type of cast - # of casts increses w/ severity of disease - indicates glomerulonephritis

Answer 44

RBC cast

Question 45

# what type of cast - seen w/ renal tubule dz - seen in ATN, interstitial nephritis, eclampsia, nephritic syndrome

Answer 45

epithelial casts

Question 46

# what type of cast - made up of various cell types in final phase of cellular degeneration - very slow tubular transit time - severe chronic renal disease (HTN nephropathy)

Answer 46

waxy/granular casts

Question 47

# what type of cast -indicates **nephrotic** syndrome, renal disease, hypothyroidism

Answer 47

fatty cast

Question 48

# what type of cast made of various cell types and indicates ESRD

Answer 48

broad cast

Question 49

colorless crystal w/ coffin lid appearance associated w/ alkaline urine & UTI (proteus species)

Answer 49

triple phosphate

Question 50

colorless hexagonal shaped crystals found in acidic urine; diagnostic of cystinuria

Answer 50

cystine crystals