chemical analysis Flashcards
chemical-impregnated absorbent pads attached to a
plastic strip.
reagent strip
care of reagent strip
ØStore with desiccant in an opaque, tightly closed container.
ØStore below 30C; do not freeze.
ØDo not expose to volatile fumes.
ØDo not use past the expiration date.
ØDo not use if chemical pads become discolored.
ØRemove strips immediately prior to use.
Quality Control of Reagent Strips
ØTest open bottles of reagent strips with known positive and negative
controls every 24 hr.
ØResolve control results that are out of range by further testing.
ØTest reagents used in backup tests with positive and negative controls.
ØPerform positive and negative controls on new reagents and newly
opened bottles of reagent strips.
ØRecord all control results and reagent lot numbers
Major regulator of acid-base content of the body
lungs and kidney
ph of first morning urine
5-6 ph
ph of Normal Random sample
4.5 - 8 ph
Causes of Acidic urine
- Emphysema
- Diabetes mellitus
- Starvation
- Dehydration
- Diarrhea
- Presence of acid- producing
bacteria (Escherichia coli) - High-protein diet
- Cranberry juice
- Medications
causes of Alkaline 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
Renal calculi formation
Determination of unsatisfactory specimens
principle of ph
DOUBLE-INDICATOR SYSTEM OF METHYL RED AND
BROMTHYMOL BLUE
color reaction for methyl red and the ph
red to yellow; 4.6 ph
color reaction for Bromthymol blue and the ph
yellow to blue (pH range 6-9)
Most indicative of renal disease
protein
nv of ph
<10mg/dL or 100mg/24h
Clinical proteinuria
≥ 30mg/dL or 300 mg/L
caused by conditions affecting the plasma prior to
reaching the kidney
pre renal proteinuria
Seen in case of multiple myeloma
bence jones protein
Frequently transient in proteinuria
ØHemoglobin
ØMyoglobin
ØAPR due to inflammation
ØNot usually discovered in routine urinalysis
Screening test:
Solubility test
Solubility test coagulates at
40-60°C (turbid)
solubility test dissolves at
100°C (clear)
confirmatory test
serum electrophoresis
glomerular/tubular dse
True renal disease
Causes of glomerular proteinuria
amyloid material, toxic substances, and the immune complexes found in lupus
erythematosus and streptococcal glomerulonephritis
causes of tubular proteinuria
exposure to toxic substances and heavy metals,
severe viral infections, Fanconi syndrome
benign proteinuria
Transient
symptoms of tubular proteinuria
strenuous exercise, high fever, dehydration, and exposure to
cold
filtered albumin can no longer be reabsorbed
tubular proteinuria
Selective filtration is impaired
glomerular proteinuria
Increased CHON, RBCs, WBCs
glomerular proteinuria
symptoms of glomerular proteinuria
Strenuous exercise, dehydration or associated with hypertension preeclamps
Appears in vertical position; disappears in horizontal position
orthostatic proteinuria
ORTHOSTATIC result
(-) 1st sample; (+) 2nd sample
Seen frequently in young adults
orthostatic proteinuria
diabetic nephropathy leading to reduced glomerular filtration and
eventual renal failure
MICROALBUMINURIA
Albumin Excretion Rate
20-200 ug/min, 30-300 mg/24hr
Albumin creatine ratio
> 3.4mg/mmol
The presence of blood as the result of injury or menstrual
contamination
Protein (Post-renal Proteinuria)
FALSE-POSITIVE of protein
◦Highly buffered alkaline urine ◦ Pigmented specimens,
phenazopyridine ◦Quaternary ammonium
compounds (detergents) ◦ Antiseptics, chlorhexidine
◦ Loss of buffer from prolonged
exposure of the reagent strip to
the specimen ◦High specific gravity
protein zyme CORRELATIONS WITH OTHER TESTS
Blood
Nitrite
Leukocytes
Microscopic
micral test principle
enzyme immunoassay
