ASO

Question 1

ASO-Latex agglutination is the ___ and ____ test for the _____ and _______measurements of antibodies to ______ in _____serum.

Answer 1

rapid ;simple ;qualitative and semi-quantitative ;Anti- Streptolysin-O (ASO); human

Question 2

When the latex reagent is mixed with a serum containing ASO ______occurs.

Answer 2

agglutination

Question 3

In acute streptococcal infection the ______is produced in response to Streptolsin antigens liberated by _______streptococci of groups __and__

Answer 3

toxic immunogenic exoenzyme Streptolysin-O (ASO) ;haemolytic ;A, C and G.

Question 4

____is important in the investigation of post-streptococcal diseases, particularly _____ and________

Answer 4

Measurement of ASO antibody titre ;acute glomerulonephritis and rheumatic fever.

Question 5

ASO Latex: 50 tests ____, 100 tests_____, 150 tests_____

Answer 5

1x2.5ml; 1x5.0ml; 2x 3.75ml

Question 6

Positive Control: 50 tests ____, 100 tests_____, 150 tests_____

Answer 6

1x0.5ml; 1x 1.0ml ;1x 1 ml

Question 7

Negative Control: 50 tests ____, 100 tests_____, 150 tests_____

Answer 7

1x0.5ml ; 1x 1.0ml ;1x 1ml

Question 8

Test Cards-Reusable: 50 tests ____, 100 tests_____, 150 tests_____

Answer 8

1 ;2 ;3

Question 9

Pipette/Stirers : 50 tests ____, 100 tests_____, 150 tests_____

Answer 9

50 100 150

Question 10

Composition of ASO latex

Answer 10

Suspension of white latex particles coated with streptolysin O

Question 11

The ASO-latex sensitivity is calibrated against the International Standard from _____, pH ____and _____

Answer 11

NIBSC ASO, pH 8.2 and preservative.

Question 12

Positive Control:

Answer 12

Human Serum with ASO >200 IU/mL and preservative

Question 13

Negative Control:

Answer 13

Animal Serum and preservative

Question 14

Precaution

The reagent is intended for______use only.

Answer 14

in vitro

Question 15

Precaution

Do not use ______

Answer 15

damaged vials

Question 16

Precaution

Although the controls which have been derived from _____origin have been tested and found to be ______ for the presence of _____,_____ as well as _____

Answer 16

human ; negative; anti-HIV, anti-HCV as well as HbsAg,

Question 17

Precaution

Protective clothing should be worn when handling the reagents, such as ______and a ________.

Answer 17

disposable gloves and a laboratory coat.

Question 18

Precaution

The reagent contains <0.1% sodium azide.

Answer 18

<0.1% sodium azide

Question 19

Precaution

____may be toxic if ingested and may react with _____ and _____ plumbing to form _______

Answer 19

lead and copper; explosive metal azides.

Question 20

Precaution

On disposal flush away with l_____ of water to prevent _____

Answer 20

large volumes ; build-up

Question 21

Storage:

Store components (latex and controls) at

Answer 21

2-8°C

Question 22

Do not f_____, as this may affect the functionality of the test

Answer 22

freeze

Question 23

Store vials in a _____ and gently mix before use

Answer 23

vertical position

Question 24

Serum stable for ____at_____. If longer sample storage is necessary, sera should be frozen at ____

Answer 24

48 hours at 2-8°C; -20°C.

Question 25

Samples should be free from contamination, ___ and ____

Answer 25

haemolysis and lipaemia

Question 26

Materials required but not supplied:

Answer 26

Mechanical rotator (set at100 r.p.m.)
Vortex mixer
9g/L saline solution

Question 27

DILUTION: Neat
ASO (IU/mL) :

Answer 27

200

Question 28

DILUTION: 1:2
ASO (IU/mL) :

Answer 28

400

Question 29

DILUTION: 1:4
ASO (IU/mL) :

Answer 29

800

Question 30

DILUTION: 1:8
ASO (IU/mL) :

Answer 30

1600

Question 31

Each run of tests should be validated with a ____ and _____control. Tests must be considered ______ if controls do not show the expected results.

Answer 31

positive and negative control; invalid

Question 32

Examine ________ for the presence or absence of clumps or agglutination immediately after removing the card from the rotator

Answer 32

macroscopically

Question 33

Reactions read after the _____ may be invalid due to drying of the reagent.

Answer 33

2 minute time

Question 34

The presence of visible agglutination indicates a content of

Answer 34

anti- streptplysin greater than equal to 200 IU/ml

Question 35

Positive sera may be titred. To titrate make serial _____in ______saline as indicated in the Semi-Quan test

Answer 35

two-fold dilutions ; 9g/L

Question 36

The serum titre is defined as

Answer 36

the recipricol of
the highest dilution showing positive agglutination.

Question 37

The approximate ASO level (IU/mL) present in the sample may be obtained

Answer 37

multiplying the titer by the limit of sensitivity (200 IU/ml)
or 200 x ASO Titre = ASO (IU/mL)

Question 38

Analytical sensitivity:

Answer 38

200 +/- 50 IU/mL

Question 39

Prozone effect

Answer 39

no prozone was detected up to 1500 IU/mL

Question 40

Diagnostic sensitivity:

Answer 40

98%

Question 41

Diagnostic specificity:

Answer 41

97%

Question 42

There is no interference:

Answer 42

Bilirubin — 20 mg/dl
Hemoglobin — 10 g/L
Lipids — 10 g/L

Question 43

T or F
Other substances may interfere.

Answer 43

T

Question 44

False positive results may be obtained in conditions such as

Answer 44

scarlet fever,
tonsilitis,
several streptococcal infections
and even in healthy carriers.

Question 45

False negative reactions may occur in

Answer 45

early primary infections
children aged between 6 months and 2 years of age.

Question 46

it is advisable that titrations on questionable cases are carried out at
_____for ______ in order to ascertain the
evolution of the disease.

Answer 46

bi-weekly intervals; 4 to 6 weeks

Question 47

T or F
single ASO determination does yield much information on the contemporary significance of the disease.

Answer 47

F; Does not yield