-
What is the normal color of urine derived from?
Urochrome
-
What forms from the oxidation of urobilinogen as urine stands and adds minimally to the normal yellow color?
Urobilin
-
What adds a slight pink pigment (usually following refrigeration), when the pigment attaches to precipitated amorphous urates?
Uroerythrin
-
What does a pale yellow urine generally indicate?
- Dilute
- Diabetes insipidus or diabetes mellitus with increased urine excretion
-
What does a dark yellow urine generally indicate?
- Concentrated specimen (first morning or strenuous exercise)
- Dehydration
-
What does a intense yellow/amber/orange urine generally indicate?
- Pyridium: (phenazopyridine) meds prescribed for UTIs
- Bilirubin: bilirubinemia occurs with liver problems, hepatitis, biliary obstruction
-
What does a yellow foam on a urine generally indicate?
Forms when urine is shaken due to the presence of conjugated bilirubin
-
What does a red/pink urine generally indicate?
- Blood
- Hemoglobin, erythrocytes
- Myoglobin (muscle trauma)
- Prophyrins
-
What does a green/blue generally indicate?
- Meds and dyes such as amitriptyline, indican, phenols
- Infections caused by Pseudomonas species
-
What does a pale brown/black generally indicate?
- Glomerular bleeding
- Denatured hemoglobin, melanin, or homogentisic acid
-
What does the sweet or fruity odor of urine indicate?
Ketone bodies (diabetic ketosis)
-
What does the maple syrup odor of urine indicate?
Maple syrup disease
-
What is the first renal function to become impaired?
Reabsorption
-
How does the refractometer work?
Measure a refractive index by comparing the velocity of light in air to the velocity of light in a solution
-
What is the normal range of specific gravity?
1.003-1.035
-
What is the term for urines with <1.010 SG?
Hyposthenuric urine
-
What is the term for urines with >1.010 SG?
Hypersthenuic urine
-
What conditions does a low specific gravity indicate?
- Loss of the kidney's ability to concentrate urine
- Presence of disease (diabetes insipidus, glomerulonephritis, pyelonephritis)
-
What conditions does a high specific gravity indicate?
- Adrenal insufficiency
- Diabetes mellitus
- Hepatic disease
- CHF
- Dehydration
- Interference from X-ray contrast media
-
How is pH regulated in the body?
- Primarily regulated by the lungs and kidneys
- Kidneys provide regulation through secretion of hydrogen ions via ammonium ions, hydrogen phosphate, and organic weak acids
- Kidneys also facilitate reabsorption of bicarbonate from the convoluted tubules
-
What do acidic pH's in urines indicate?
- High protein diets
- After normal sleep
- Respiratory/metabolic acidosis
- Uncontrolled diabetes mellitus
-
What does an alkaline pH in urine indicate?
- Excreted in urine after in response to gastric HCl
- Vomiting
- Increased consumption of veges
- Renal tubular acidosis
- Respiratory/metabolic alkalosis
- UTIs
-
What indicators are used on the reagent strip?
- Methyl red
- Bromthymol blue
-
What indicator is used on the reagent strip to detect protein?
Tetrabromphenol blue
-
What is the normal range for protein in a random and 24 hr urine?
- Random: <10 mg/dL
- 24 hr: 100 mg/24 hr
-
What can urine protein indicate?
- Renal disease
- Tubular reabsorption problems
- Increased low molecular weight proteins
- Glomerular membrane damage caused by toxic agebts , lupus, or streptococcal glomerularnephritis
- Multiple Myeloma
-
What is a key indicator of Multiple Myeloma?
Bence Jones protein in the urine
-
What is:
Produced due to a proliferative disorder of plasma cells as seen in Multiple Myeloma
Proteins are light chain monoclonal immunoglobulins
Bence Jones protein
-
What condition can occur in cold temps and as a result of exercise, fever, dehydration, late pregnancy, and orthostatic/postural proteinuria in young adults
Benign proteinuria
-
What is a useful evaluation for patients with renal complications of diabetes mellitus and what are abnormal results?
- Microalbumin
- 30-299 mg albumin/g creatinine
-
What test is:
Performed only for comparison with protein level to rule out microalbuminuria
Provides an assurance that the water volume of the sample is NOT influencing the protein concentration
Creatinine
-
How will you get a false positive and false negative for creatinine?
- False positive: None
- False negative: Ascorbic acid
-
What test is most commonly used to detect diabetes mellitus?
Glucose
-
What is present in:
Diabetes mellitus
Impaired tubular reabsorption seen in Fanconi syndrome
Advanced tubular renal disease
CNS damage
Thyroid disorders
Pregnancy
Glucosuria
-
What is the enzyme used to detect glucose on reagent strips?
Glucose oxidase
-
What gives false positives and false negatives for glucose on the reagent strip?
- False positive: Antibiotics, Ascorbic acid and other reducing agents
- False negative: NONE
-
How does the Copper reduction test work?
Glucose reduces copper sulfate to cuprous oxide
-
What are included in ketones?
- 3 Intermediate products of fatty acid metabolism:
- Acetone
- Acetoacetic acid
- Beta-hydroxybutyric acid
-
What is the clinical significance of ketones in urine?
- Uncontrolled diabetes mellitus
- Insulin dosage monitoring
- Electrolyte imbalance
- Dehydration due to excessive carb loss such as vomiting, starvation, exercise, and rapid weight loss
-
What indicator is used in the reagent strips to detect ketones and how?
- Sodium nitroprusside is used to measure acetoacetic acid
- The addition of glycine permits the measurement of acetone and acetoacetic acid
-
What test:
Is a nitroprusside and glycine tablet used to detect ketones
Gives an enhanced color reaction
Permits serial dilutions to be done
Acetest
-
What method uses beta-hydroxybutyrate dehydrogenase to detect the presence of beta-hydroxybutyric acid?
Enzymatic method
-
What types of blood are in a urine?
- Hematuria (intact RBCs)
- Hemoglobinuria (Hgb in the urine)
- Myoglobin (Hgb-like protein found in muscle tissue
-
How do you screen for myoglobin in urine?
- Use ammonium sulfate to precipitate Hgb out of the urine
- The urine supernatant is then filtered and tested with a reagent strip
- Positive is myoglobin
-
What will give you false positive and false negative results with a reagent strip with blood?
- False positive: Vegetable peroxidase and E. coli peroxidase
- False negatives: High levels of ascorbic acid or nitrites, formalin preservatives, captopril (hypertension meds)
-
How is bilirubin produced?
- Hgb is metabolized into iron, protein, and protoporphyrin
- Protoporphyrin is converted to bilirubin by the reticuloendothelial system cells
- Bilirubin binds to albumin for transport to the liver as unconjugated bilirubin
-
What clinical conditions cause bilirubinuria?
- Hepatitis
- Cirrhosis
- Biliary obstruction
- Early liver disease when conjugated bilirubin enters the circulation
-
What is the water soluble form of bilirubin and excreted in the urine?
Conjugated bilirubin
-
How is conjugated bilirubin removed from the body?
Excreted in the urine
-
What form of bilirubin is NOT water soluble and cannot be excreted in urine?
Unconjuated bilirubin
-
How is unconjugated bilirubin removed from the body?
- Bilirubin binds to albumin for transport to the liver as unconjugated bilirubin
- In the liver, bilirubin is conjugated with glucuronic acid to form bilirubin diglucuronide
- Bilirubin diglucuronide goes into the intestines and is reduced to urobilinogen via bacterial action and excreted in the feces as urobilin
-
What condition is indicated when urine:
Bilirubin POS
Urobilinogen NORMAL
Bile duct obstruction
-
What condition is indicated when urine:
Bilirubin NEG
Urobilinogen POS
- Hemolytic disease
- (Unconjugated form increases in the plasma)
-
What reaction is used to detect bilirubin in the urine?
Diazonium salt
-
What tablet is used to confirm a reagent strip bilirubin?
Ictotest
-
What causes a false positives and false negatives for bilirubin?
- False positives: pigmented urine
- False negatives: specimen is too old, excessive exposure to light, ascorbic acid, and nitrite
-
What product is:
Formed from Hgb metabolism
Produced from the reduction of bilirubin by bacteria in the small intestine
Urobilinogen
-
What conditions cause an increased urobilinogen?
- Early liver disease
- Hepatitis
- Hemolytic anemias
-
What reagent is used to detect urobilinogen in a reagent strip?
- Ehrlich's reagent or
- Diazo dye
-
What gives false positives and false negatives for urobilinogen on a reagent strip?
- False positive: Pigmented urine
- False negative: Improper storage, high levels of nitrite
-
What is a rapid test for UTIs on a reagent strip?
Nitrite
-
What conditions does a positive Nitrite indicate?
- Cystitis (bladder infection)
- Pyelonephritis
-
What can give false positives and false negatives for nitrite in a reagent strip?
- False positives: standing urine, pigmented urine
- False negatives: Ascorbic acid, antibiotics, bacteria that do not reduce nitrate, inadequate time in the bladder, heavy concentration of bacteria
-
What conditions does a positive leukocyte esterase indicate?
- UTI
- Infammation of the urinary tract
-
What gives false positives and false negatives for leukocyte esterase on the reagent strip?
- False positives: pigmented urine, strong oxidizing agents
- False negatives: Increased glucose, protein, ascorbic acid, lymphocytes, high specific gravity
-
What can high levels of ascorbic acid (Vit C) do to a urinalysis reagent strip?
- False positive: Glucose
- False negatives: Creatinine, Blood, Bilirubin, Nitrite, Leukocyte esterase
-
What test is used to monitor hydration and dehydration, loss of renal tubular concentrating ability, and diabetes insipidus?
Specific gravity
-
What causes false positives and false negatives for a specific gravity on a reagent strip?
- False positive: Increased protein or ketones
- False negatives: If urine pH is >6.5 then add 0.005 to the reading
|
|
