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Clinical Lab > Lecture 2 > Flashcards

Lecture 2 Flashcards

1
Q

Renal Disease

Signs and Symptoms

A
  • Malaise, HA, visual disturbances
  • Flank pain, renal colic N/V
  • Low urine output
  • +/- painful urination (dysuria), hematuria or pyuria
  • Hypertension
  • Edema (protein loss)
  • Malar rash
  • Bleeding
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2
Q

Renal Disease

Laboratory Findings

A
  • Increases serum blood urea nitrogen (BUN) and serum Creatine.
  • Decrease creatine clearance
  • Oliguria (
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3
Q

Blood Urea Nitrogen

A

Measures the amount of urea nitrogen in the blood.

Urea is formed in the liver as the end product of protein metabolism.

Urea is filtered by the glomerulus but partially reabsorbed by the tubules

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4
Q

BUN

Normal range

A

***10-20mg/dL

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5
Q

BUN

Serum Levels is Dependent on

A

Glomerular filtration rate (GFR)
Protein content in the diet
Tissue metabolism
Proximal tubule reabsorption (dependent od GFR)
Functional status of the hepatic urea cycle

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6
Q

Increased in BUN

A

CHF, Renal Failure
Shock, burns, dehydration, diuretics
Excessive protein intake, TPN
GI bleeding

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7
Q

Decrease in BUN

A

Malnutrition
Liver Failure
*** Pregnancy, SIADH (volume overload)

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8
Q

Azotemia

A

*** Nitrogen retention seen with elevated BUN

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9
Q

Chronic Renal Failure

A

*** >3 months deterioration in renal failure

consequence of the loss of functioning nephrons

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10
Q

Uremia

A

clinical term that describes the patients sign as symptoms when end-stage renal failure.

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11
Q

Serum Creatine

A

Waste product in the blood that comes from muscle activity.

  • Its the breakdown product of creatine phosphate
  • it directly related to skeletal muscle mass.

***The most common used indicator of renal function

Used to calculate the creatine clearance which correlates with the glomerular filtration rate GFR

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12
Q

Creatine normal range

A

.5-1.2 mg/dL

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13
Q

Increased Creatine Levels

A

Renal disease, hypovolemia and tissue necrosis, CHF heart failure, RM, burns

Drugs: ACE inhibitors, aminoglycosides (gentamicin), cimetidine (H2 blocker), NSAIDs, chemotherapeutics (cisplatin), antibiotics (trimethoprim, cefoxitin), **lithium, ***contrast dye, statins, diuretics, creatine supplements in body builders.

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14
Q

Decreased

A

Debilitation (not moving their muscle mass), decreased muscle mass
Pregnancy, SIADH (volume overload)

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15
Q

Acute Kidney failure

Pre-renal, Renal, Post-renal

A

Most things are acute
Pre-renal - hyper-perfusion of kidneys (dehydration, anemia, heart failure)
Renal- Acute tubular necrosis, Acute interstitial nephritis, Glomerulonephritis
Post-renal (think obstruction)
BPH, prostate cancer, Bladder/cervical CA obstructing ureters, stone (renal lithiasis), kinked foley catheter

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16
Q

BUN/ Crt ratio

Prerenal, renal, postrenal

A

Prerenal (>20:1)
BUN reabsorption is increased
Dehydration or hypoperfusion suspected

Renal (

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17
Q

Novel AKI Biomarkers

A

Serum and urine cystatin C

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18
Q

Creatinine clearance (CCr)

A

Volume of blood plasma that is cleared of creatinine per unit of time and is a useful measure for approximating the GFR

Creatinine Clearance (CCr) is useful to help
Detect renal dysfunction
Calculate dose intervals for nephrotoxic drugs
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19
Q

Glomerular Filtration Rate (GFR)

A

Volume filtered from the kidney glomerular capillaries into the Bowman’s capsule per unit of time

Best test to measure kidney function and determine stage of kidney disease

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20
Q

GFR and Creatinine

A

Inverse relationship

If GFR declines by 50%, Plasma Creatinine doubles

Clearance of creatinine is suitable estimate of GFR

The lower the GFR, the more significant the kidney damage

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21
Q

*Urine Osmolality

ncrease

A 
Syndrome Inappropriate ADH Secretion (SIADH)
Dehydration
Glycosuria
Adrenal Insufficiency
High protein diet
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22
Q

*Urine Osmolality

Decreased

A

Diabetes Insipidus (diuretic effect urination a lot)
Excessive hydration (oral or intravenous)
Acute renal insufficiency
Glomerulonephritis

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23
Q

Urinalysis

componenets

A 
Components
Physical examination
Color 
Clarity
Specific gravity
Volume
Odor
Chemical examination (Reagent strip)
Microscopic examination
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24
Q

Color of urine

A 
Color
Normal – yellow or amber
Due to a yellow pigment called urochrome
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
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25
Q

Clarity

A

Normal – clear or transparent

Cloudy/Turbid – possible bacteria or alkalinity

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26
Q

Odor

A

Normal – “urinoid”
Fruity or sweet odor – diabetic ketoacidosis
Ammoniacal odor – long standing urine
Pungent odor – urinary tract infections

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27
Q

(Volume)

Oliguria

A

decrease in normal daily urine output.

Dehydration, burns, diarrhea, vomiting.

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28
Q

(Volume)

Anuria

A

cessation of urine flow

Serious damage to the kidney

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29
Q

(Volume)

Nocturia

A

increase in the nocturnal excretion of urine

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30
Q

(Volume )

Polyuria

A

increase in the daily urine output

Diuretics, Diabetes mellitus, diabetes insipidus

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31
Q

Specific Gravity

A

Specific Gravity
Measure of the weight of solutes in water in the urine
Solutes include urea, chloride, sulfate and phosphate
Specific gravity is a crude indicator of Urine Osmolality
Reagent strip specific gravity
Gives important insight into the patient’s hydration status

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32
Q

Water Specific Gravity

A

Water Specific Gravity: 1.000

Desirable Range: 1.010-1.025
Normal Range: 1.005 to 1.030

Hydration status
1.020 indicates relative dehydration

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33
Q

Water Specific Gravity dtermination

A

Reagent dipstick

Measures the concentration of ions and gives an indirect measure of specific gravity

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34
Q

Increased Urine Specific Gravity

A

Glycosuria or increased urine protein

Syndrome of inappropriate antidiuretic hormone

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35
Q

Decreased Urine Specific Gravity

A 
Diuretic use
Diabetes insipidus (decreased ADH)
Adrenal insufficiency 
Aldosteronism 
Impaired renal function
36
Q

Specimen CollectionTiming

A

Timing
First morning is most concentrated
Random specimen is most common

Midstream clean-catch is preferred

Urine should be examined within one hour after voiding
Refrigerate specimen if this cannot be done

37
Q

Chemical Examination

Reagent Strip

A 
pH
Specific Gravity
Protein
Glucose
Ketones
Bilirubin
Nitrites
Leukocyte Esterase
38
Q

Urine pH

A

Measure of the kidney’s ability to preserve normal hydrogen ion concentration in maintenance of acid-base balance

Desirable Range: 6-6.5
Normal Range: 4.5-8

Affected by diet
More acidic: cranberries, high protein
More alkaline: citrate, vegetables, dairy products

39
Q

Urine pH

A

Persistent alkaline urine (pH 7-8) suggests:
Urinary tract infection
Renal Tubular Acidosis
Kidneys are unable to adequately excrete hydrogen ions
Vomiting
Metabolic alkalosis
Vegetarian diet (pure vegans)
Alkalizing drugs (antibiotics, bicarbonate)
Proteus infection
Converts urea to ammonia producing an ammonia odor

40
Q

Urine pH

Persistent acidic urine (pH 5-6) suggests

A 
Acidosis
Diabetes Mellitus
Starvation
Diarrhea
Uric acid calculi
Drugs (ammonium chloride)
41
Q

Urine Specific Gravity

increased

A

Presence of glucose or protein

42
Q

Urine Specific Gravity

Decreased

A

Diabetes insipidius

Decreased antidiuretic hormone ADH

43
Q

Urine Protein

A

Sensitive indicator of glomerular and tubular renal function

Normally, 150 mg of protein daily (10-20 mg/dL)

44
Q

Urine Protein

A

Reagent on dipstick is mainly sensitive to albumin (globulins, hemoglobin, fibrinogen, Bence Jones)

Normal Range: Negative or Trace

Abnormal Result
1+: 30 mg of protein per dL
2+: 100 mg/dL
3+: 300 mg/dL
4+: 1,000 mg/dL
45
Q

Common causes of proteinuria

Transient proteinuria

A

Congestive heart failure, dehydration, emotional stress, exercise, fever, orthostatic (postural) proteinuria, seizures, pregnancy

46
Q

Common causes of proteinuria

Persistent proteinuria

A

Glomerular causes (nephropathies, DIABETES MELLITUS, infections, malignancies (Multiple myeloma: Bence-Jones protein), DRUGS (NSAIDS, penicillamine, ACE-inhibitors), sickle cell disease, tubular causes (interstitial nephritis)

47
Q

Urine Protein

False Negatives

A

Dilute urine

Acidic urine

48
Q

Urine Protein

False Positive

A 
Medications
Penicillin, Sulfonamides
Contamination
Hematuria, pus, semen, vaginal secretions
Alkaline urine
49
Q

Urine Glucose

A

Glucose is normally filtered by the glomerulus, but it is reabsorbed in the proximal tubule
Excreted in urine when the plasma level exceeds the kidney threshold of 180 mg/dL or when there is a defect in the reabsorption of glucose

50
Q

Glucosuria

A 
Diabetes Mellitus
Pregnancy
Cushing’s syndrome
Liver and pancreatic disease
Impaired tubular reabsorption
51
Q

Urine Ketones

A

Ketones are the products of fat metabolism (rather than normal glucose metabolism)

Normal result: negative for ketones

52
Q

Ketonuria

A

Diabetic ketoacidosis, fasting/starvation, carbohydrate-free diets (Atkins), pregnancy

53
Q

Urine Blood

A

May be in the form of intact RBCs or hemoglobin from lysed RBCs

Normal result: negative

Causes
Menses, vigorous exercise, anticoagulation therapy
Myoglobinuria – rhabdomyolysis, myocardial infarction
Hemolytic anemia, infections, calculi, tumors

54
Q

Evaluating Hematuria

A 
Complete UA (dipstick and microscopic)
Culture
KUB
IV Pyelogram
Cystoscopy
Urine cytologic exam
Renal biopsy
55
Q

Urine Bilirubin

A

Normal result: negative

Bilirubinuria
Liver disease (hepatitis, cirrhosis)
**Obstructive biliary tract disease
-Biliary stasis interferes with the normal excretion of conjugated bilirubin via the intestinal tract.
-This causes a buildup in the bloodstream resulting bilirubinuria.

56
Q

Urine Urobilinogen

A

Conjugated bilirubin in the intestinal tract is converted by bacterial action to urobilinogen
Small amount is normally excreted in the urine (up to 4 mg/d), but the major excretion is in the feces

Normal result: normal or trace

57
Q

Urine Urobilinogen

increased

A

Increased
Any condition that causes an increase in the production in bilirubin
Hemolytic anemias, malaria
Any disease that prevents the liver from normally removing the reabsorbed urobilinogen from the portal circulation
Infectious or toxic hepatitis, congestive heart failure

58
Q

Urine Urobilinogen

Decreased

A

Decreased
Any process that decreases bilirubin in the stool
Diminishing liver function
Obstruction of the bile ducts (cholelithiasis)
Antibiotic therapy
Suppression of normal intestinal flora

59
Q

Urine Nitrite

A

Rapid screen for the detection of bacteria that are capable of reducing nitrates to nitrites.
-Escherichia coli (most common), Enterobacter, Proteus, Klebsiella, Pseudomonas, Citrobacter.

Positive test indicates that these organisms are present in significant numbers
> 10,000 per mL

60
Q

Urine Nitrite

E.coli

A

Test is highly specific but not highly sensitive
Positive result is helpful, but a negative result does not rule out Urinary Tract Infection

Normal result: negative

False Positives
-Vaginal contaminant, strips exposed to air

False Negatives
-Low nitrate diet, urine not in the bladder for at least 4 hours, bacteria that lack nitrate reductase enzyme

61
Q

Urine Leukocyte Esterase

A

Test that indicates whether white blood cells are present in the urine
Cystitis, Pyelonephritis, Urethritis (STI)

Normal result: negative

False Positives
Vaginal cellular contamination or trichomonads

62
Q

*Confirmatory Tests

A

Ictotest – bilirubin (purple)

Clinitest – glucose

Sulfosalicylic acid – protein (hazy)

Acetest – Ketones (purple)

63
Q

*Urine Microscopy

A

Required Reading: How to use a Microscope Powerpoint on Moodle

Summary
Total magnification is the ocular lens (10x) x objective lens 
-Scanning lens 10x  X  4x  = 40x
-Low power  10x  X  10x  = 100x
-High power  10x  X 40x  = 400x
64
Q

Specimen

A

Fresh sample of 10-15 mL of urine is centrifuged at 1,500-3,000 rpm for 5 minutes
The supernatant is decanted and the sediment resuspended in the remaining liquid
A single drop is transferred to a clean glass slide, and a cover slip is applied

65
Q

Prussian blue stain

A

Hemosiderin (iron)

66
Q

Clue cells

A

Squamous epithelial cells covered with bacteria Gardenerella vaginalis

Bacterial Vaginosis
Fishy odor

67
Q

Trichomonas vaginalis

A

Sexually transmitted urogenital parasite

1-2 times bigger than WBC

Rapid erratic movement

68
Q

Fungus

A

Vaginal candidiasis

69
Q

Urine Crystals

A

Commonly found in urine sediment

Rarely clinically significant

Reported as few, moderate, many, or too numerous to count (TNTC) under microscopic high power

70
Q

Cystine crystals

A

Flat colorless hexagonal plates

Favor acidic urine

Result of an inherited metabolic defects that prevents the reabsorption of cystine

71
Q

Cholesterol crystals

A

Retangular plates with a notch in one or more of the corners

May be seen in those with nephrotic syndrome

72
Q

Leucine crystals

A

Yellow spheres with concentric and radial strias

Polarized light – “maltese cross”

Seen in liver failure

73
Q

Tyrosine crystals

A

Fine brownish needles

May be seen with liver disease

74
Q

Bilirubin crystals

A

Yellow spheres with spicules

Conjugated bilirubin

Liver disease

75
Q

Urinary
Casts

A

Formed in distal and collecting tubules

Only a few hyaline or granular casts are normal

76
Q

Normal Urinary Casts

A

Casts contain Tamm-Horsfall protein, which is a mucoprotein secreted only by renal tubular cells, and forms the matrix of casts

77
Q

Hyaline casts

A

Hard to visualize as they have no inclusions

78
Q

Granular casts

A

Degenerated cellular casts or protein aggregation

Classified as finely granular or coarsely granular

79
Q

Abnormal Urinary Casts

A

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

80
Q

Urine Hemosiderin

A

Protein that stores iron

Normal result: negative

Appears as a dark yellow-brown pigment

Positive
Hemochromatosis
Chronic hemolytic anemia
Paroxysmal nocturnal hemoglobinemia

81
Q

Urinary Pregnancy Tests

A
  • Human chorionic gonadotropin (hCG) is produced by the syncytiotrophoblast cells of the placenta after implantation (a few days after conception).
    • hCG should double every 2-3 days for the first 6 weeks.
  • Most chemical tests for pregnancy look for the presence of the beta subunit of hCG in blood or urine.
82
Q

Urinary Pregnancy Tests

A

Normal results

Negative: 25 IU/L

83
Q

Urinary Pregnancy Tests

False negatives results

A

Testing done too early
Test has too high hCG detection threshold
Medications: diuretics and promethazine

84
Q

Urinary Pregnancy Tests

False positive result

A

Medications containing the hCG molecule
Non-pregnant production of the hCG moledule
Medications (chlorpromazine, phenothiazines, methadone)
Tests read after the suggested reaction time

85
Q

Infertility treatments

A

hCG injections as part of infertility treatment will test positive on pregnancy tests regardless of her actual pregnancy status

Some infertility drugs (clomid) do not contain hCG hormone

86
Q

*Conditions that may produce elevated hCG

A

Testicular tumors
Ovarian germ cell tumors
Choricocarcinoma
Gestational trophoblastic disease

87
Q

Qualitative vs Quantitative

A

Quantitative blood tests

Can detect hCG levels as low as 1 IU/L

Clinical Lab (1 decks)

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