Renal Testing

Question 1

What does BUN tell you?

Answer 1

Measures amount of nitrogen in the blood in the form of urea.
Only a rough measurement.

Question 2

What are causes of Increased BUN?

Answer 2

"Azotemia"
Dehydration, Starvation, pyelonephritis, ATN, Bladder Obs
Hypovolemia
Shock
CHF
MI
GI Bleed
Protein Supps

Question 3

What can cause an increased BUN?

Answer 3

Liver failure
Overhydration 
Neg Nitrogen balance-Malnutrition/malabsorption
Preggo
Nephrotic Synd

Question 4

What is the GFR?

Answer 4

Sum of filtration rates in all functioning nephrons

Question 5

What is the normal value for GFR?

Answer 5

Men- 130 mL/Min 1.73m2

Women- 120 mL/Min 1.73m2

Question 6

What is the Urinary Creatinine?

Answer 6

Creatinine is a catabolic product of creatinine phosphate

Slight increase after large meals (meat)

Question 7

What causes Inc Creatinine

Answer 7

Disease effecting renal function

Question 8

What causes Dec Creatinine?

Answer 8

Dec muscle mass

• debilitation
• musc dystrophy
• myasthenia gravis
• elderly
• children

Question 9

What is the BUN: Creatinine ratio?

Answer 9

Prerenal >20:1
Post Renal or normal 10-20:1
Renal

Question 10

What does the UA-Glucose tell you?

Answer 10

Inability of the kidney to reabsorb filtered glucose in the proximal tubule
Abn High plasma Conc

Question 11

What is the Normal UA pH?

Answer 11

4.5-8.0

Usually 5.0- 6.5

Question 12

What is the UA Specific Gravity?

Answer 12

Measure of the Conc of Particles in the urine.
Low- Overhydration or renal dis
High-Dehydration

Question 13

What is Leukocyte Esterase in UA?

Answer 13

Leukocytes in urine

WBCs

Question 14

What is Nitrates in UA?

Answer 14

Many bacteria produce reductase which can reduce Nitrates to nitrites

Question 15

What is Ketones in UA?

Answer 15

Normal is NO ketones
Present: DM and hyperglycemic
Alcoholism
Fasting/starvation/dehydration

Question 16

What does UA blood tell you?

Answer 16

Follow up with microscopy

Question 17

What can give you a false pos for Blood in urine?

Answer 17

Alkaline urine
Contam with ox agents used to clean perineum
Semen
Myoglobin

Question 18

What will be seen on UA in Rhabdomyolysis?

Answer 18

Muscle Pain AND Blood on dipstick

Question 19

What are the protein levels on UA?

Answer 19

Trace to 4+
1^ detects albumin
Must screen 300-500mg per day to be detected

Question 20

What are possible causes of Hematuria?

Answer 20

Glomerular
Renal- Tubular/interstitial/vascular
Urologic- Tumors, calculi, infection

Question 21

What type of Epithelial Cells are of diagnostic importance?

Answer 21

Epith in Casts

Question 22

What are the causes of RBC Casts?

Answer 22

Glomerulonephritis

Question 23

What are the causes of Fatty Casts?

Answer 23

Nephrotic Synd

Hypothyroidism

Question 24

What are the causes of Waxy/broad Casts?

Answer 24

Advanced renal fail

Question 25

What are the types of Crystals in the urine?

Answer 25

Cysteine
CaOxalate
Uric Acid
Struvite#####

Question 26

What are the FENA Levels in UA?

Answer 26

2% Acute tubular Necrosis

Innacurate in Pt on diuretics

Question 27

What are the Glomerular causes of PErsistant Proteinuria >500mg/day

Answer 27

Nephritic: inflammation on histo exam
Nephrotic: not inflammatory
Proteinuria
Hyperlipidemia

Question 28

What does eosinophils in the urine tell you?

Answer 28

Allergic interstitial nephritis

Question 29

What are the reasons for Kidney Biopsy?

Answer 29

Isolated Glom hematuria w/ prot
Nephrotic
Acute Nephritic Synd
Acute renal failure