PART 1: routine examination of urine (week 4) Flashcards
plastic strips that contain one or more chemically impregnated test sites on an absorbent pad. Each absorbent pads contain one or more reagents and these
reagents react with the urine, producing a distinct color. The color produced will be compared to the comparator block
Reagent Strips (dip stick)
1) Mix the urine
2) Insert reagent strip
3) Remove excess urine
4) Time according to manufacturer’s directions.
5) Compare test areas closely with corresponding color
charts.
6) Hold strip horizontally and close to the color chart.
Reagent Strips (dip stick) PROCEDURE
- With desiccant (used to absorb moisture) in opaque (black container bottle), tightly capped containers. Most common reason for the discoloration of the strip
is the uncapped containers - Room temperature (below 30°C)
- Keep strips in their original container
DO STORAGE AND GENERAL PRECAUTION
- Expose the strips to volatile fumes
- Touch the test areas
- Use if the chemical pads become discolored
- Use past the expiration date
- Also: Do not transfer test strips to another vial, prolong the dipping of the test (1 second is all it takes), and touch the test zones with you fingers
DON’T STORAGE AND GENERAL PRECAUTION
Sources of erros
- Unmixed specimen
- Strip in urine for extended period
- Excess urine in the strip (run over bet chemicals)
- Refrigerated specimen
If the urine specimen will not be mixed, the formed elements such as RBCs and WBCs will just settle at the bottom and will not be detected
Unmixed specimen
Leaching of reagents from the pad.
*Leaching - lalabas
Strip in urine
for extended
period
Distortion of colors
What to do to prevent run-over of chemicals?
Blot the edge of the strip and hold the strip
horizontally
Excess urine
in the strip
(run-over bet
chemicals)
- False negative enzymatic tests. For example, glucose which has an enzyme called glucose oxidase that doesn’t react in cold temperatures.
- To avoid this, allow the specimen to reach room temperature before dipping the strip
Refrigerated
specimen
Tested with known positive or negative controls.
QUALITY CONTROL
1) Test using different reagents or methodologies to detect the
same substances as detected by the reagent strips
2) Same or greater sensitivity or specificity
3) Tablets and liquid chemicals
CONFIRMATORY TEST
- It reflects the ability of the kidney to maintain normal hydrogen ion concentration in plasma and extracellular
fluid. - The organs that play a role in acid
base balance are the kidneys and the lungs
REACTION/ pH
‒ To maintain acid-base balance in the body; kidneys secrete hyrogen ions and bicarbonate should be reabsorbed
‒ Blood must buffer and eliminate excess acids
‒ Buffering capacity of blood depends on bicarbonate ions (HCO3- )
‒ Secretion of hydrogen ions causes reabsorption of
bicarbonates
pH
i. Secretion of H+ in the form of NH4+, hydrogen
phosphate & weak organic acids
ii. Reabsorption of bicarbonate from the filtrate in the
PCT.
Maintenance of acid-base balance in the body via the kidneys is made possible through
Respiratory or metabolic
acidosis
Respiratory or metabolic
alkalosis
Defects in renal tubular secretion and re-absorption of acids and bases
Renal tubular acidosis
Determination of unsatisfactory specimen. An unsatisfactory pH is when the specimen reaches a
pH of 9 or a pH of 4
- Increased protein and meat diet
- Cranberries
- Acid producing bacteria
- Starvation
- Dehydration
- Diarrhea
- Diabetes mellitus
Acid urine
- Increased fruits and vegetables
- Citrus
- Less acidic after meal (alkaline tide)
- Renal tubular acidosis
- Urease producing bacteria
- Hyperventilation
- Old specimen
Alkaline urine
methyl red changes
color from red to yellow
pH range of 4 to 6
bromthymol blue changes color from yellow to blue in the
pH range of 6 to 9
The pH range measured by the reagent strips
5 to 9
The color changes from orange to yellow, green
At pH 5
color changes to blue when the pH reaches
pH 9.0
Methyl red (red to yellow)
pH 4-6
Bromthymol blue (yellow to blue)
pH 6-9
- a pH meter w/ glass electrode
- it measures the voltage caused by the H+ ions in the urine
- Dipped into a solution
pH electrode
- Measured by titrating an aliquot of 24 hr.
- urine with 0.1N NaOH with pH 7.4 as an end point
Titrable acidity
1) Most of the albumin is not filtered
2) Filtered albumin is reabsorbed by tubules
Protein
Important test is the _____ because if it is increased, there could be problems with glomerular basement membrane or
podocytes
albumin
a) Refers to protein in urine in sufficient quantities to be detected by most clinical tests
- Proteins are derived from the plasma and the urinary tract
b) Very small amount of albumin is present in urine compared to blood level
- Most of the albumin is not filtered by the glomerulus
- Much of the filtered albumin is reabsorbed by the tubules
c) Protein determination is the most indicative of renal disease among the routine chemical tests
Proteinuria
Types of proteinuria
- Physiologic or functional
- Postural or thostatic
- Accidental or false or pseudo
- Pathologic
- Seen in excessive ingestion of proteins, prolonged cold baths, late pregnancy, fever, emotional stress, strenuous exercise. This type of albuminuria is_____
- 0.5 g/day
- Resolved with rest for 2-3 days
Causes:
1) Dehydration
2) Exercise
3) Congestive Heart Failure -less blood, less
urine is formed
4) Cold exposure (prolonged cold baths)
5) Fever
6) Late pregnancy
7) Emotional stress
Physiologic or functional
- transient
Urine protein :
i. (+) day; vertical (nakatayo)
ii. (-) night; horizontal (nakahiga) - kasi di
napepress yung renal vein
Postural/Orthostatic
a) First voided urine: (-)
protein
b) 2 hrs standing or
walking : (+) protein
Tests for this proteinuria
Urine is contaminated directly or indirectly with albuminous fluids, pus cells, blood, vaginal discharge (e.g. vaginitis and cystitis -inflammation of the bladder
Accidental
or False or
Pseudo
- Renal diseases and indicates increased
permeability of the glomerular filter - With defect in glomerular filter (endothelial cells, glomerula filtrate barrier, and podocytes), proteins can easily pass through.
- If we see protein in the urine, it is because of problems in
the glomerulus
Pathologic
- Heavy proteinuria
>4g per day - Moderate
proteinuria - Minimal proteinuria
QUANTIFICATION (amount in 24 hrs)
Nephrotic syndrome:
- ↓Serum albumin
- ↑Lipid in blood & urine
- Granular cast
- Fatty cast
- Oval fat body
Heavy proteinuria
>4g per day
1 to 4 g/day
Moderate
proteinuria
Minimal proteinuria
<1 g/day
“large molecules can pass through
because the glomerulus has
problems”
- > 3-4 g/day
- (-) charge on GBM is ↓
- Urine (+) large protein a2 macroglobulin
B-lipoprotein - Glomerulonephritis
Sira ang glomerulus kaya masyadong marami ang protein
GLOMERULAR
PATTERN
“problems with the
renal tubular
reabsorption”
- 1-2 g/day
- Urine (+) small protreins
- a1 microglobulin
- b2 microglobulin
- Fanconi, cystinosis
Intact ang glomerular filtration membrane but the problem is in the tubules
TUBULAR
PATTERN
” umaapaw usmobrang dami kaya nakikita sa urine”
- This is due to the overflow of excess levels of protein in the circulation
- It can be seen with hemoglobin, myoglobin or immunoglobulin loss into the urine
Overflow proteinuria
Causes of proteinuria
- Conditions affecting the blood before it reached the kidney
- Multiple myeloma (Bence Jones Protein)
- Intravascular hemolysis (hemoglobin)
- Myoglobin
- Acute phase reactants
Prerenal (before)
- Associated with true renal disease, either because of glomerular or tubular damage
- Glomerular disorders
- Tubular proteinuria
- Orthostatic proteinuria
- Microalbuminuria
Renal
- Protein is added to the urine specimen as it passes through the lower urine tract
- Lower UTI
- Menstrual contamination
- Vaginal secretions
Post renal
