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