ASO Flashcards
ASO-Latex agglutination is the ___ and ____ test for the _____ and _______measurements of antibodies to ______ in _____serum.
rapid ;simple ;qualitative and semi-quantitative ;Anti- Streptolysin-O (ASO); human
When the latex reagent is mixed with a serum containing ASO ______occurs.
agglutination
In acute streptococcal infection the ______is produced in response to Streptolsin antigens liberated by _______streptococci of groups __and__
toxic immunogenic exoenzyme Streptolysin-O (ASO) ;haemolytic ;A, C and G.
____is important in the investigation of post-streptococcal diseases, particularly _____ and________
Measurement of ASO antibody titre ;acute glomerulonephritis and rheumatic fever.
ASO Latex: 50 tests ____, 100 tests_____, 150 tests_____
1x2.5ml; 1x5.0ml; 2x 3.75ml
Positive Control: 50 tests ____, 100 tests_____, 150 tests_____
1x0.5ml; 1x 1.0ml ;1x 1 ml
Negative Control: 50 tests ____, 100 tests_____, 150 tests_____
1x0.5ml ; 1x 1.0ml ;1x 1ml
Test Cards-Reusable: 50 tests ____, 100 tests_____, 150 tests_____
1 ;2 ;3
Pipette/Stirers : 50 tests ____, 100 tests_____, 150 tests_____
50 100 150
Composition of ASO latex
Suspension of white latex particles coated with streptolysin O
The ASO-latex sensitivity is calibrated against the International Standard from _____, pH ____and _____
NIBSC ASO, pH 8.2 and preservative.
Positive Control:
Human Serum with ASO >200 IU/mL and preservative
Negative Control:
Animal Serum and preservative
Precaution
The reagent is intended for______use only.
in vitro
Precaution
Do not use ______
damaged vials
Precaution
Although the controls which have been derived from _____origin have been tested and found to be ______ for the presence of _____,_____ as well as _____
human ; negative; anti-HIV, anti-HCV as well as HbsAg,
Precaution
Protective clothing should be worn when handling the reagents, such as ______and a ________.
disposable gloves and a laboratory coat.
Precaution
The reagent contains <0.1% sodium azide.
<0.1% sodium azide
Precaution
____may be toxic if ingested and may react with _____ and _____ plumbing to form _______
lead and copper; explosive metal azides.
Precaution
On disposal flush away with l_____ of water to prevent _____
large volumes ; build-up
Storage:
Store components (latex and controls) at
2-8°C
Do not f_____, as this may affect the functionality of the test
freeze
Store vials in a _____ and gently mix before use
vertical position
Serum stable for ____at_____. If longer sample storage is necessary, sera should be frozen at ____
48 hours at 2-8°C; -20°C.
Samples should be free from contamination, ___ and ____
haemolysis and lipaemia
Materials required but not supplied:
Mechanical rotator (set at100 r.p.m.)
Vortex mixer
9g/L saline solution
DILUTION: Neat
ASO (IU/mL) :
200
DILUTION: 1:2
ASO (IU/mL) :
400
DILUTION: 1:4
ASO (IU/mL) :
800
DILUTION: 1:8
ASO (IU/mL) :
1600
Each run of tests should be validated with a ____ and _____control. Tests must be considered ______ if controls do not show the expected results.
positive and negative control; invalid
Examine ________ for the presence or absence of clumps or agglutination immediately after removing the card from the rotator
macroscopically
Reactions read after the _____ may be invalid due to drying of the reagent.
2 minute time
The presence of visible agglutination indicates a content of
anti- streptplysin greater than equal to 200 IU/ml
Positive sera may be titred. To titrate make serial _____in ______saline as indicated in the Semi-Quan test
two-fold dilutions ; 9g/L
The serum titre is defined as
the recipricol of
the highest dilution showing positive agglutination.
The approximate ASO level (IU/mL) present in the sample may be obtained
multiplying the titer by the limit of sensitivity (200 IU/ml)
or 200 x ASO Titre = ASO (IU/mL)
Analytical sensitivity:
200 +/- 50 IU/mL
Prozone effect
no prozone was detected up to 1500 IU/mL
Diagnostic sensitivity:
98%
Diagnostic specificity:
97%
There is no interference:
Bilirubin — 20 mg/dl
Hemoglobin — 10 g/L
Lipids — 10 g/L
T or F
Other substances may interfere.
T
False positive results may be obtained in conditions such as
scarlet fever,
tonsilitis,
several streptococcal infections
and even in healthy carriers.
False negative reactions may occur in
early primary infections
children aged between 6 months and 2 years of age.
it is advisable that titrations on questionable cases are carried out at
_____for ______ in order to ascertain the
evolution of the disease.
bi-weekly intervals; 4 to 6 weeks
T or F
single ASO determination does yield much information on the contemporary significance of the disease.
F; Does not yield
