PRELIM-chemical examination of the urine Flashcards
Simple, rapid means for performing medically significant chemical
analysis of urine
reagent strip
The
two major types of reagent strips are manufactured under
the trade names
Multistix (Siemens Healthcare Diagnostics,
Deerfield, IN)
Chemstrip (Roche Diagnostics, Indianapolis,
IN).
Chemical-impregnated absorbent pads are attached to a plastic strip
reagent strip
for the reporting, we follow _____ value. From trace, 1+, 2+, 3+, or 4
Semiquantitative
3 types of reagent strip
- 4 parameters
-10 parameters - 11 parameters
what are the 4 parameters in a 4-parameter type of reagent strip?
glucose - 35s
specific gravity - 45s
pH - 60s
protein 60s
what are the 10 parameters in a 10-parameter reagent strip?
glucose, SG, ph, protein ketone, blood, nitrite, bilirubin, urobilinogen, leukocytes
why do we need to blot the urine?
to prevent runover
what is the other substance we can measure in an 11-parameter reagent strip?
Ascorbic acid
what are the parameters corresponding time?
glucose - 30s
bilirubin - 30 s
ketone - 40 s
specific gravity - 45 s
blood - 60s
pH - 60 s
protein - 60s
urobilinogen - 60 s
nitrite - 60 s
leukocytes - 120s
Care of Reagent Strip
- Store with desiccant in an opaque, tightly closed container.
- Store below 30C; Do not freeze
- Do not expose to volatile fumes
- Do not use past the expiration date
- Do not use if chemical pads are discolored
- Remove strips immediately prior to
standard temperature we can store the reagent strip
below 30* C
Quality control of Reagent Strips
- Test open bottles of reagent strips with known positive and
negative controls every 24 hr.
o Depends on the laboratory, sometimes every shifts - Resolve control results that are out of range by further testing
- Test reagents used in backup tests with positive and negative
control - Perform positive and negative controls on new reagent and newly
opened bottles of reagent strips - Record all control results and reagent lot number
Major regulator of acid-base content of the body
Lungs and kidney
Why do we need to determine the pH of the urine? Or what is the clinical
significance of pH?
we can determine if the problem came from the tubules of the kidney or from the lungs.
If there’s no problem with the tubules, most probably the problem is with the lungs that is why some doctors request ABG or arterial blood gas analysis to check the reason for pH disturbance
which part of the tubule is affected is there’s a secretion of the HYDROGEN ION in the urine?
proximal tubules
which part of the tubule is affected is there’s a secretion of the AMMONIUM in the urine?
Distal convoluted tubule
what is the normal ph of the first morning urine in a healthy individual
pH 5.0-6
. In respiratory or metabolic acidosis not related to renal function disorders, the urine is ___
acidic or basilic?;
acidic
If respiratory or metabolic alkalosis is present, the urine is ___
alkaline
calcium oxalate, a frequent constituent of renal calculi, precipitates primarily in ____
acidic and
not alkaline urine.
maintaining urine in alkaline pH discourages formation of the calculi.
true or false
true
Maintaining an acidic urine can be valuable in treating
‘____ caused by urea-splitting organisms
because they do not multiply as readily in an acidic medium
urinary tract infections
has long been used as a home remedy for minor bladder in
fections because it inhibits the colonization of certain urinary
pathogens.
cranbrry juice
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
true or false
true, that is why we should not re use containers
what is the normal ph level/range for a normal urine random sample in a healthy individual?
4.5 pH - 8.00 pH
what are the cause of the acidic pH in the urine?
Emphysema
Diabetes Mellitus
Starvation
Dehydration
Diarrhea
Presence of acid-producing bacteria
High protein diet
Cranberry juice
Medications
(Methenamine, Mandelate
[Mandelamine],
Fosfomycin tromethamine)
what are the cause of the alkaline pH in the urine?
Hyperventilation
Vomiting
Renal tubular acidosis
Presence of Urease-producing bacteria
Vegetarian Diet
Old Specimens
Clinical Significance of pH
- Respiratory or metabolic acidosis/ketosis
- Respiratory or metabolic alkalosis
o Renal tubular acidosis → Detects in renal tubular
secretion and reabsorption of acids and bases - Renal Calculi/stone formation
- Treatment of urinary tract infections
- Precipitation/Identification of crystals
- Determination of unsatisfactory specimens
In acidic conditions, which carbonates are formed, is it amorphous urates or phosphate?
amorphous urate
In basic conditions, which carbonates are formed, is it amorphous urates or phosphate?
amorphous phosphate
the pH level on the reagent strip ranges from — to —
pH 5 to pH 9
orange to green
is there substance that can interfere with the pH test using the reagent strip?
No known substance to cause interference
what is the principle of pH in the reagent strip reaction?
Principle → Double-indicator system of methyl red and bromothymol blue
For the references in pH, for the methyl red, the pH level ranges from – to –
red to yellow (pH range 4-6)
For the references in pH, for the bromothymol blue, the pH level ranges from – to –
yellow to blue (pH range 6-9)
pH can be correlate with other test such as the
Nitrite
Leukocytes
Microscopic
the protein we detect in the urine is the
albumin
a low molecular weight, it is easily
excreted after the filtration of the glomerulus.
Albumin
it is an indicative of the renal disease particularly in the filtration
albumin/proteinuria
Other proteins
include small amounts of serum and tubular microglobulins are called
__
They are as well produced by the renal
tubular epithelial cells; and proteins from prostatic, seminal,
and vaginal secretions.
Tamm-Horsfall protein (uromodulin)
Uromodulin is routinely produced in
the ___
distal convoluted tubule
normal value of protein in urine
<10 mg
higher than 10 mg in urine is called
proteinuria
what is the clinical proteinuria level or range
≥ 30mg/dL or 300mg/L
a type of proteinuria that is Caused by conditions affecting the PLASMA prior to reaching the kidney
Pre-renal Proteinuria
pre renal transient reasons of increased level of albumin/glucose
hemoglobin,
myoglobin, and the acute phase reactants associated with
infection and inflammation.
Seen in case of multiple myeloma
Bence Jones Protein
a confirmatory test if the protein really is a myeloma or a bence jones protein is the
Serum electrophoresis
what is the screening test for bence jones protein?
Solubility test
characteristics of soluble test
o Coagulates at 40-60°C (Turbid)
o Dissolves when tempt reaches 100°C 9 (Clear)
o Filter at 100°C and observe for turbidity as it cools to 40
60°C
Proteinuria associated with true renal disease may be the result
of either glomerular or tubular damage.
Renal Proteinuria
glomerular damage might be caused by the following
o Amyloid material
o Toxic substances
o Immune complexes found in lupus erythematosus and
streptococcal glomerulonephritis
transient reasons of renal proteinuria
Strenuous exercise, dehydration or associated with hypertension
pre-eclampsia (pregnant women)
transient reason of pre-renal proteinuria
o Hemoglobin
o Myoglobin
o APR due to inflammation
o Not usually discovered in routine urine
a type of proteinuria wherein there will be some Disorders affecting tubular reabsorption
- Filtered albumin can no longer be reabsorbed
Tubular (renal) proteinuria