Quiz #2 Flashcards
Erythropoietin
Hormone released in response to hypoxia in renal circulation and stimulates erythropoiesis in the bone marrow
Renin
Enzyme that breaks down angiotensinogen to
angiotensin I
Calcitriol
Increases blood calcium by promoting intestinal absorption of calcium and increasing renal tubular reabsorption of calcium
Renal disease lab findings:
Increased serum blood urea nitrogen (BUN) and
serum creatinine
Decreased creatinine clearance
Oliguria (
Blood Urea Nitrogen:
Measures the amount of urea nitrogen in the blood
BUN depends on:
GFR
Diet protein intake
Tissue metabolism
Proximal tube reabsorption
Increased BUN cause:
CHF Renal Failure Shock, burns, etc. Excessive protein intake GI Bleeding
Decreased BUN cause:
Malnutrition
Liver failure
Pregnancy, SIADH
Azotemia:
Nitrogen retention seen with elevated BUN
Chronic Renal Failure (CRF):
> 3 months deterioration in renal failure
Uremia:
end-stage renal failure
Serum Creatinine:
Waste product in the blood that comes from muscle activity
Acute Kidney Injury:
Azotemia (elevated BUN and creatinine)
Either pre renal, renal, or post renal
BUN/Cr ratio:
Prerenal (>20:1)
Renal (
AKI biomarkers:
Serum and urine cystatin C
Neutrophil gelatinase-associated lipocalin
(NGAL)
Kidney injury molecule 1 (KIM-1)
Interleukin 19 (IL-18)
N-acetyl-glucosaminidase
Liver fatty acid-binding protein (L-FABP)
Serum Cr:
Increased: Renal disease, hypovolemia & tissue necrosis
Decreased: Debilitation, decreased muscle mass, Pregnancy, SIADH
Creatinine Clearance (CCr):
Volume of blood plasma that is cleared of creatinine per unit of time and is a useful measure for approximating the GFR
Cockcroft-Gault formula
Detects renal dysfunction
GFR:
Volume filtered from the kidney glomerular capillaries into the Bowman’s capsule per unit of time
Relationship between GFR and Creatine:
Inverse
Urine Osmolality (Uosm):
Evaluates the concentrating ability of kidney
Urine Osmolality (Uosm):
Increased: SIADH, Dehydration
Decreased: Diabetes Insipidus (diuretic effect), Excessive hydration
Urinalysis components:
1. Physical examination • Color • Clarity • Specific gravity • Volume • Odor 2. Chemical examination (Reagent strip) 3. Microscopic examination
Urine color:
- Normal – yellow or amber
- Dark yellow – ? Dehydration
- Colorless - ? dilute urine or polyuria
- Red or red-brown – blood or hemoglobin
- Dark brown or black – alkaptonuria or malignant melanoma
- Yellow-brown to yellow-green -Bilirubin or bile pigments
Urine clarity:
Normal – clear or transparent
Cloudy/Turbid – possible bacteria or alkalinity
Urine odor:
Fruity or sweet odor – diabetic ketoacidosis
Ammoniacal odor – long standing urine
Pungent odor – urinary tract infections
Urine volume:
-Oliguria – decrease in normal daily urine output
-Dehydration, burns, diarrhea, vomiting
-Anuria – cessation of urine flow
-Serious damage to the kidney
-Nocturia – increase in the nocturnal excretion of
urine
-Polyuria – increase in the daily urine output ▪ Diuretics, Diabetes mellitus, diabetes insipidus
Urine Specific Gravity:
Measure of the weight of solutes in water in the urine
Gives insight into hydration
High: glycosuria, SIADH
Low: Diuretic use, decreased ADH
Specific gravity ranges:
Desirable Range: 1.010-1.025
Normal Range: 1.005 to 1.030
1.020 indicates relative dehydration
How to measure specific gravity:
Urinometer: weighted with mercury
Refractometer: handheld; measures refractive index
Reagent dipstick: Measures the concentration of ions and gives an indirect measure of specific gravity
Urine collection time:
Morning: urine is concentrated
Midstream is preferred
Should be examined within 1 hour; refrigerate it cannot
Urine osmolality ranges:
> 850 mOsm/kg (with 12-14 hr fluid restriction)
50-1200 mOsm/kg (random, depending on fluid intake)
Reagent Strip is used to determine:
- pH
- Specific Gravity
- Protein
- Glucose
- Ketones
- Bilirubin
- Nitrites
- Leukocyte Esterase
Urine pH:
Measure of the kidney’s ability to preserve normal hydrogen ion concentration in maintenance of acid-base balance
Normal urine pH:
Desirable Range: 6-6.5
Normal Range: 4.5-8
More acidic: cranberries, high protein
More alkaline: citrate, vegetables, dairy products
Persistant urine alkaline urine pH suggests:
UTI (pH 7-8)
Persistent acidic urine (pH 5-6) suggests:
Acidosis Diabetes Mellitus Starvation Diarrhea Uric acid calculi Drugs (ammonium chloride)
Urine protein:
Sensitive indicator of glomerular and tubular renal function
Normally,
Microalbuminuria:
excretion of 30-150 mg of protein daily
Proteinuria:
excretion of > 150 mg of protein daily (10-20 mg/dL)
Urine protein ranges:
Normal = trace
Abnormal = 1+: 30 mg of protein per dL 2+: 100 mg/dL 3+: 300 mg/dL 4+: 1,000 mg/dL
Urine protein causes:
Transient proteinuria - CHF, stress, exercise
Persistent proteinuria - Diabetes, drugs, malignancies (multiple myeloma = Bence-Jones protein)
Urine ketones (ketone urea):
Ketones are the products of fat metabolism
Causes: Diabetic ketoacidosis, fasting/starvation, carbohydrate-free diets (Atkins), pregnancy
Urine blood (hematuria):
Either lysed or intact RBC
Normal = negative
- Menses, vigorous exercise, anticoagulation therapy
- Myoglobinuria – rhabdomyolysis, myocardial infarction
- Hemolytic anemia, infections, calculi, tumors
Bilirubinuria:
Normal = negative
- Liver disease (hepatitis, cirrhosis)
- Obstructive biliary tract disease
Urine urobilinogen:
normal = negative or trace
Conjugated bilirubin in the intestinal tract is converted by bacterial action to urobilinogen
Increased urine urobilinogen causes:
Any condition that causes an increase in the
production in bilirubin (ie. hemolytic anemia)
Any disease that prevents the liver from normally removing the reabsorbed urobilinogen from the portal circulation (i.e.. CHF, infectious or toxic hepatitis)
Decreased urine urobilinogen causes:
Any process that decreases bilirubin in the stool
Diminishing liver function
Obstruction of the bile ducts (cholelithiasis)
Antibiotics - decreased intestinal flora
Urine nitrites:
Rapid screen for the detection of bacteria that are capable of reducing nitrates to nitrites (E. coli)
Positive = >10,000/mL
Urine nitrite tests:
Test is highly specific but not highly sensitive
Urine Leukocyte Esterase:
Test that indicates whether white blood cells are present in the urine
Cystitis, Pyelonephritis, Urethritis (STI)
Normal = negative
Tests to confirm:
Ictotest – bilirubin (purple)
Clinitest – glucose
Sulfosalicylic acid – protein (hazy)
Acetest – Ketones (purple)
Urine microscopy viewing:
Scanning lens 10x X 4x = 40x Low power 10x X 10x = 100x High power 10x X 40x = 400x
Urine microscopy findings:
Cells & Cellular Elements Crystals
Casts
Bacteria
Urine microscopy specimens:
Fresh sample of 10-15 mL of urine is centrifuged
at 1,500-3,000 rpm for 5 minutes
Take out supernatant
Use single drop
Urine microscopy staining:
-Sternheimer-Malbin stain
Cells and casts
-Toluidine blue
Differentially stains various cell components
-Sudan III or oil red O stain
Stains lipids
-Prussian blue stain
Hemosiderin (iron)Cellular findings:
Squamous epithelial cells - not a clean catch
Clue cells - Squamous epithelial cells covered with bacteria Gardenerella vaginalis
Trichomonas vaginalis - Sexually transmitted urogenital parasite (1 to 2 times larger that WBC, rapid erratic movement)
Fungus - Vaginal candidiasis
Bacteria
Urine Crystals:
Commonly found in urine sediment
Rarely clinically significant
Reported as few, moderate, many, or too numerous to count (TNTC)
Normal crystals in acidic urine (urates):
Uric acid crystals
Amorphous urates
Calcium oxalate crystals
Urine crystals, amorphous:
Yellow-brown granules
Often found in clumps
Urine crystals, Calcium oxalate:
Common cause
of urolithiasis
One of the toxic effects in ethylene glycol poisoning
Urine crystals, uric acid:
Yellow to red to orange in color
Appear in many shapes
Normal alkaline urine crystals:
Triple phosphate - Coffin lid appearance
Calcium phosphate - Large flat-shaped plates or wedge shaped prisms, rosettes
Ammonium bitrate crystals - “Thorn apple” shape, yellow-brown
Calcium carbonate crystals - Small colorless granules
or dumbbells
Abnormal crystals in acidic or neutral urine:
Cystine crystals Cholesterol crystals Leucine crystals Tyrosine crystals Bilirubin
Urinary Casts:
Formed in distal and collecting tubules
Only a few hyaline or granular casts are normal
Normal urinary casts:
Hyaline casts
Granular casts
Abnormal urinary casts:
Cellular casts:
-Red blood cell casts
Signify glomerular disease
-White blood cell casts
Associated with pyelonephritis and infection
-Renal tubular epithelial cell casts
Tubular diseases like tubular necrosis or drug toxicity
Acellular cast:
-Waxy cast
Seen in severe renal failure
Urine Hemosiderin:
Protein that stores iron
Normal result: negative
Appears as a dark yellow-brown pigment
Positive:
Hemochromatosis
Chronic hemolytic anemia
Paroxysmal nocturnal hemoglobinemia
Urinary Pregnancy Tests:
Human chorionic gonadotropin (hCG)
Tests look for beta subunit or hCG in blood or urine
Urine pregnancy test results:
Negative: 25 IU/L
Home pregnancy test, should be done first thing in the morning
Urine pregnancy test results:
False negative:
- Testing done too early
- Test has too high hCG detection threshold
- Medications: diuretics and promethazine
False positive:
- Medications containing the hCG molecule
- Non-pregnant production of the hCG molecule
- Medications (chlorpromazine, phenothiazines, methadone)
- Tests read after the suggested reaction time
Urine pregnancy tests, conditions that may produce elevated hCG:
- Testicular tumors
- Ovarian germ cell tumors
- Choricocarcinoma
- Gestational trophoblastic disease
hCG Blood tests:
Qualitative:
Urine: 20-50
Blood: 5-10
Quantitative:
Can detect as low as 1 IU/L
