Lesson 3: Chemical Examination of Urine Flashcards
Two major types of reagent strips are manufactured
Multistix (Siemens Healthcare Diagnostics)
Chemistrip (Roche Diagnostics)
Chemical reagent strips consist of chemical-___________ attached to a plastic strip
chemical-impregnated absorbent pads
The pH of normal random specimens can range from?
4.5 to 8.0
Formed elements, such as RBCs and WBCs sink to the bottom of the specimen and will be undetected when?
Specimens are not mixed
How to avoid runover phenomenon?
Blot the pad
Allowing excess urine to remain on the strip after its removal from the specimen can produce a ________ between chemicals on adjacent pads, producing distortion of colors
runover
Reading time for: Leukocyte esterases (LE)
30 to 120 seconds
Reagent strips are to be stored in?
Room temperature (below 30C) and are never refrigerated
True or False
Reagent strips must be checked with both positive and negative controls according to the frequency established by the laboratory policy
True
Reagent strips are packaged in opaque containers with _________ to protect then from light and moisture
Dessicant
Why is distilled water not recommended as a negative control for reagent strips?
Because reagent strip reactions are designed to perform at ionic concentrations similar to urine
A more alkaline pH is found after meals which is called as an?
Alkaline tide
Identify if Acid Urine or Alkaline Urine
Medications like methenamine, mandelate, fosfomycin, tromethamine
Acid Urine
Phenazopyridine compounds could give of what color reaction in the urine?
Phenazopyridine = orange pigment
A healthy individual usually produces a slightly acidic pH in a first morning specimen, what is the pH range?
5.0 to 6.0
It is the major serum protein found in normal urine
Albumin
True or False
Maintaining a Alkaline pH discourages renal calculi formation
True, it is because Calcium Oxalate precipitates at acidic pH and not in alkaline pH
Identify if Acid Urine or Alkaline Urine
Presence of E. coli
Acid Urine (Acid-producing bacteria = E. coli)
Identify if Acid Urine or Alkaline Urine
Presence of urease-producing bacteria
Alkaline Urine
Identify if Acid Urine or Alkaline Urine
Renal Tubular Acidosis
Alkaline Urine
It is a frequent constituent of renal calculi that precipitates primarily in ACIDIC and not alkaline urine
Calcium oxalate
Does maintaining an acidic urine valuable in treating UTIs caused by urea-splitting organisms>
Yes, because urea-splitting bacteria do not multiply as readily in an acidic medium
Why do people with UTIs advised to drink cranberry juice?
Because cranberry juice inhibit the colonization of some urinary pathogens
Technical Tip: Collecting specimens in containers other than the single-use-laboratory-supplied containers can produce a pH above 8.5 if alkaline detergent remains in the container
Wow! Thank you! Strasinger for this wonderful information!
Clinical proteinuria is indicated at?
30 mg/dL or greater (300 mg/L)
Reagent strips use a double indicator system of ________ and _________
Methyl red and Bromothymol blue
Double-Indicator System color change:
Methyl Red:
Bromothymol Blue:
Methyl Red: Red to Yellow (4 to 6 pH range)
Bromothymol Blue: Yellow to Blue ( 6 to 9 pH range)
Note: 5 to 9 pH range (5 = orange to yellow to green to 9 = deep blue)
Bacterial growth by certain organisms in a specimen may cause a marked alkaline shift in the reagent strip because of the the conversion of urea to _______
ammonia
These are monoclonal immunoglobulin light chains that are markedly elevated in patients with cases of multiple myeloma (proliferative disorder of the immunoglobulin-producing plasma cells)
Bence-Jones Proteins
Of the routine chemical tests performed on urine, the most indicative of renal disease is the?
protein determination
This type of proteinuria is usually transient and caused by increased levels of low-molecular-weight plasma proteins such as hemoglobin, myoglobin, and acute-phase reactants
Prerenal Proteinuria
This is often associated with early renal disease, making the urinary protein test an important part of any physical examination
Proteinuria
Normal urine usually contains a small amount of protein which is?
<10 mg/dL or 100 mg per 24 hours
This is a glycoprotein produced routinely in the ascending loop of henle
Tamm-Horsfall protein (THP) / Uromodulin
The development of ____________ leading to a reduced glomerular filtration and eventual renal failure is a common occurrence in people with both Type 1 and Type 2 DM
Diabetic nephropathy
Conditions that present the glomerular membrane with abnormal substances like and cause proteinuria due to glomerular damage:
Amyloid material
Toxic substances
Immune complexes (Lupus Erythematosus)
Streptococcal glomerulonephritis
These are included in what type of proteinuria?
Renal Proteinuria
A persistent benign proteinuria occurs frequently in young adults and is termed as?
orthostatic proteinuria / postural proteinuria
Fanconi Syndrome is associated with what type of renal disorder?
Tubular Disorder
Traditional reagent strip testing for protein uses this principle to produce a visible COLORIMETRIC REACTION
protein error of indicators
Protein area of the the Reagent Strip contains these indicators.
Multistix:
Chemstrip:
Acid buffer:
Multistix: Tetrabromophenol blue
Chemstrip: 3,3,5,5, tetrachlorophenol or 3,4,5,6-tetrabromosulfonphthalein
Acid buffer: maintain pH
This contains a “gold-labeled antihuman albumin antibody-enzyme conjugate”
Micral-Test reagent strip
It is a “cold precipitation” test that reacts equally with all forms of protein
Sulfosalicylic acid test (SSA)
Unbound conjugates in Micral-Test are removed in what zone?
Captive zone
True or False
In the Micral-Test, the amount of color produced represents the amount of albumin present in the urine
Ture
In the Micral-Test, the conjugated enzymes reacts with the substrate, producing colors ranging from ______ to ______
White to red
In the ImmunoDip reagent strip, it produces two blue bands (top and bottom band), which is the bound and unbound particles
Top band: Bound particles (urine albumin)
Bottom band: Unbound particles
For the Micral-Test reagent strip, the bound and unbound conjugates move up the strip by what action?
Wicking action
True or False
In the Micral-Test, the color is compared with a chart on the reagent strip bottle after 1 minute
Results range: 0 to 10 mg/dL
True
Results interpretation for ImmunoDip reagent strip
Darker bottom band:
Equal color:
Darker top band:
Darker bottom band: <1.2 mg/dL (Negative)
Equal band: 1.2 to 1.8 mg/dL (Borderline)
Darker top band: 2.0 to 8.0 mg/dL (Positive)
The principle for the reagent strip for creatinine is based on the what?
Pseudoperoxidase activity of copper-creatinine complexes
Because of its value in the detection and monitoring of DM, this test is the chemical analysis performed most frequently on urine
Glucose Test
Reagent strips for Creatinine contain?
Copper sulfate
3,3,5,5-Tetramethylbenzidine (TMB)
Diisopropyl benzene dihydroxyperoxide (DBDH)
For creatinine in the reagent strip, the expected color for the reaction is?
Orange through green to Blue
The onset of hyperglycemia ang glycosuria is normally around the __ month of pregnancy
6th month of pregnancy
In mothers with gestational diabetes, since glucose can cross the placenta, the excess glucose transferred to the baby is stored as fat, resulting in a larger baby termed as?
Macrosomia
Reagent Strip (Glucose Oxidase) Reaction Chromogen color
Potassium Iodide:
Tetramethylbenzidine:
Potassium Iodide: green to brown
Tetramethylbenzidine: yellow to green
What do manufacturers incorporate this in test pads which oxidizes ascorbic acid so that it cannot interfere with the oxidation of the chromogen
Iodate
Glycosuria in the absence of Hyperglycemia is referred to as?
Renal glycosuria
The test relies on the ability of glucose and other substances to reduce copper sulfate to cuprous oxide in the presence of alkali and heat
Copper Reduction Test (Clinitest)
Most clinically significant reducing sugar affecting the Clinitest for GLUCOSE
Galactose
Ketonuria shows a deficiency in _______, indicating the need to regulate dosage.
Insulin
Copper Reduction Test: Result
Negative:
Positive:
Negative: Copper Sulfate (CuSO4)(Blue)
Positive: Cuprous Oxide (Cu2O)(Orange/Red)
Clinitest tablets are very hygroscopic and should be stored in their original, tightly closed packages.
A strong _____ color in the unused tablets suggest deterioration due to moisture accumulation, as does vigorous tablet fizzing
strong blue color
Galactose in the urine of newborns suggests an inborn error of metabolism wherein there is a lack of what enzyme?
GALT (Galactose-1-phosphate uridyl transferase)
Clinitest is subject to interference by reducing sugars like?
Galactose
Fructose
Pentose
Lactose
Galactose in the urine of the newborn represents an?
Inborn error of metabolism
It is a reducing sugar frequently found in the urine of nursing mothers
Lactose
This is a non-reducing sugar which does not react with Clinitest or glucose oxidase strips. Therefore, it cannot be used as a control or in preparation of a laboratory exercise for glucose testing
Sucrose
Intermediary products of “FAT” metabolism
Ketones
Percentage of ketones found in the urine in descending order of concentration
B-hydroxybutyrate (78%)
Acetoacetic acid (20%)
Acetone (2%)
Normally, measurable amounts of ketones do not appear in the urine because all the metabolized fat is completely broken down into _______ and _______
Carbon dioxide and water
Testing for urinary ketones is most valuable in the management and monitoring of what type of diabetes?
Type 1 Diabetes Mellitus (Insulin-dependent)
Both acetone and B-hydroxybutyric acid are produced from?
Acetoacetic acid
Reagent strip tests use this reaction to measure KETONES
sodium nitroprusside (nitroferricyanide)
Large amounts of levodopa and medications containing sulfhydryl groups, including __________ and _____, may produce atypical color reaction in Ketone Reagent Strip
MESNA (mercaptoethane sulfonate sodium)
Captopril
In the sodium nitroprusside reaction, the acetoacetic acid in an alkaline medium reacts with sodium nitroprusside to produce what color?
Purple color
Does sodium nitroprusside reaction for ketone measure B-hydroxybutyrate?
No, it does not,, but it measure acetone only when glycine is present
