Anti-Streptolysin O (ASO)

Question 1

Streptolysin O is a hemolytic factor produced by most strains of?

Answer 1

Group A beta-hemolytic streptococci (S. pyogenes)

Question 2

what are streptococci

Answer 2

are gram positive cocci in chain, non-motile, facultative anaerobes

Question 3

Toxins and Enzymes Produced by S. pyogenes

Answer 3

toxin: streptolysin O and streptolysin S
enzymes: DNAse and streptokinase

Question 4

oxygen-labile (sensitive to oxygen)

Answer 4

streptolysin o

Question 5

oxygen-stable

Answer 5

Streptolysin S

Question 6

Hemolytic Streptococci with no hemolysis

Answer 6

Gamma Hemolvtic Streptococcus

Question 7

Gamma Hemolvtic Streptococcus are commonly seen with?

Answer 7

enterococcus on blood agar plates

Question 8

Hemolytic Streptococci - Clear complete hemolysis on blood agar plates

Answer 8

Beta Hemolytic

Question 9

Beta Hemolytic Strep is divided into two groups

Answer 9

-Group A (S. pyogenes)
-Group B (S. agalactiae)

Question 10

Group A (S. pyogenes) in bacitracin & CAMP test

Answer 10

Bacitracin-sensitive, CAMP-negative

Question 11

Group B (S. agalactiae) in bacitracin & CAMP test

Answer 11

Bacitracin-resistant, CAMP-positive

Question 12

Differentiates S. pyogenes from S. agalactiae

Answer 12

CAMP & Bacitracin Test

Question 13

Standard method for Group B Strep identification

Answer 13

Lancefield Precipitation Test

Question 14

Hemolytic Streptococci - Green with partial hemolysis

Answer 14

Alpha Hemolytic

Question 15

Alpha Hemolytic is differentiated through what test

Answer 15

Optochin Test

Question 16

alpha hemolytic is divided into 2 groups

Answer 16

• S. pneumoniae
• T. viridans

Question 17

differentiate s.pneumoniae and t.viridans

Answer 17

• S. pneumoniae: Optochin-sensitive, bile-soluble
• T. viridans: Optochin-resistant, bile-insoluble

Question 19

Streptolysin O vs. Streptolysin S

Answer 19

Streptolysin O:
• Active only in reduced state
• Antigenic (produces ASO antibodies)

Streptolysin S:
• Active in both reduced and oxidized
• Non-antigenic (no anti-Strep S test)

Question 20

Specifies on the chromatin breakdown during apoptosis/necrosis

Answer 20

DNAse

Question 21

Causes complete hemolysis of blood agar; breaks down chromatin

Answer 21

Streptokinase

Question 23

It is a specific neutralizing antibody produced after infection with these organisms

Answer 23

ANTI-STREPTOLYSIN O

Question 24

when does anti strep o appear

Answer 24

appears in serum from 1 week - 1 month after onset of a streptococcal infection.

Question 25

what does anti strep o do

Answer 25

It combines and neutralizes the hemolytic activity of streptolysin O

Question 26

Normal Values (NV) for ASO

Answer 26

• Children: <150 UL/mL • Adults: <200 UL/mL

Question 27

ASO Incubation Period

Answer 27

• 2 weeks: Start of signs and symptoms • 5 weeks: Peak levels

Question 28

Used to confirm false negatives

Answer 28

DNAse Test

Question 29

Determines an organism’s ability to hydrolyze DNA for carbon and energy

Answer 29

DNAse Test

Question 30

Uses of ASO Test

Answer 30

Diagnoses conditions from streptococcal infections, especially: • Rheumatic fever • Glomerulonephritis

Question 31

ASO Antibody: 1-3 weeks

Answer 31

Antibodies begin to appear

Question 32

ASO Antibody: 3-5 weeks

Answer 32

Peak levels

Question 33

ASO Antibody: Up to 6 months

Answer 33

Antibody levels decline to insignificant levels

Question 34

what does persistent high titer indicate

Answer 34

recurrent or chronic infection

Question 35

antibody that appears in patients serum days after infection

Answer 35

Antibodies (IgG)

Question 36

ASO test principles: reaction

Answer 36

ASO binds to Streptolysin O (SLO) and inhibits hemolysis.

Question 37

how is the amount of ASO estimated

Answer 37

Patient serum is diluted until hemolysis is completely inhibited.

Question 38

Screens for significant ASO titer increase.

Answer 38

ASO Latex Slide Test

Question 39

Determines ASO antibody titer.

Answer 39

ASO titration test

Question 40

principle of Rapid ASO Latex Agglutination Test

Answer 40

Visible agglutination occurs when ASO antibodies in serum react with latex particles coated with SLO antigen.

Question 41

specimen used for Rapid ASO Latex Agglutination Test

Answer 41

Clear, hemolysis-free serum.

Question 42

storage temp for aso reagents and specimens

Answer 42

2-8C

Question 43

is slight sedimentation after refrigeration normal

Answer 43

yes

Question 44

Specimen Type

Answer 44

Fresh serum from centrifuged clotted blood.

Question 45

Short-Term Storage

Answer 45

2 - 8°C for up to 7 days.

Question 46

Long-Term Storage

Answer 46

• -20°C if stored for 3 months or more.