Renal Testing Flashcards
What does BUN tell you?
Measures amount of nitrogen in the blood in the form of urea.
Only a rough measurement.
What are causes of Increased BUN?
"Azotemia" Dehydration, Starvation, pyelonephritis, ATN, Bladder Obs Hypovolemia Shock CHF MI GI Bleed Protein Supps
What can cause an increased BUN?
Liver failure Overhydration Neg Nitrogen balance-Malnutrition/malabsorption Preggo Nephrotic Synd
What is the GFR?
Sum of filtration rates in all functioning nephrons
What is the normal value for GFR?
Men- 130 mL/Min 1.73m2
Women- 120 mL/Min 1.73m2
What is the Urinary Creatinine?
Creatinine is a catabolic product of creatinine phosphate
Slight increase after large meals (meat)
What causes Inc Creatinine
Disease effecting renal function
What causes Dec Creatinine?
Dec muscle mass
- debilitation
- musc dystrophy
- myasthenia gravis
- elderly
- children
What is the BUN: Creatinine ratio?
Prerenal >20:1
Post Renal or normal 10-20:1
Renal
What does the UA-Glucose tell you?
Inability of the kidney to reabsorb filtered glucose in the proximal tubule
Abn High plasma Conc
What is the Normal UA pH?
4.5-8.0
Usually 5.0- 6.5
What is the UA Specific Gravity?
Measure of the Conc of Particles in the urine.
Low- Overhydration or renal dis
High-Dehydration
What is Leukocyte Esterase in UA?
Leukocytes in urine
WBCs
What is Nitrates in UA?
Many bacteria produce reductase which can reduce Nitrates to nitrites
What is Ketones in UA?
Normal is NO ketones
Present: DM and hyperglycemic
Alcoholism
Fasting/starvation/dehydration
What does UA blood tell you?
Follow up with microscopy
What can give you a false pos for Blood in urine?
Alkaline urine
Contam with ox agents used to clean perineum
Semen
Myoglobin
What will be seen on UA in Rhabdomyolysis?
Muscle Pain AND Blood on dipstick
What are the protein levels on UA?
Trace to 4+
1^ detects albumin
Must screen 300-500mg per day to be detected
What are possible causes of Hematuria?
Glomerular
Renal- Tubular/interstitial/vascular
Urologic- Tumors, calculi, infection
What type of Epithelial Cells are of diagnostic importance?
Epith in Casts
What are the causes of RBC Casts?
Glomerulonephritis
What are the causes of Fatty Casts?
Nephrotic Synd
Hypothyroidism
What are the causes of Waxy/broad Casts?
Advanced renal fail
What are the types of Crystals in the urine?
Cysteine
CaOxalate
Uric Acid
Struvite#####
What are the FENA Levels in UA?
2% Acute tubular Necrosis
Innacurate in Pt on diuretics
What are the Glomerular causes of PErsistant Proteinuria >500mg/day
Nephritic: inflammation on histo exam
Nephrotic: not inflammatory
Proteinuria
Hyperlipidemia
What does eosinophils in the urine tell you?
Allergic interstitial nephritis
What are the reasons for Kidney Biopsy?
Isolated Glom hematuria w/ prot
Nephrotic
Acute Nephritic Synd
Acute renal failure
