• Improper dispensing of the entire reagent from dropper

Immediately after performing the test, transfer the contents of the

reagent dropper back into the reagent vial

Ensure that no reagent is left behind in the dropper. Close the cap of

the reagent vial properly and store it back at 2–8°C

Do not freeze the reagent vial

12. Cross contamination due to the usage of the same mixing stick Separate mixing stick should be used for mixing the controls and the

sample

Contd...

Serology/Immunology 653

Possible causes Solutions

1. The sensitivity of our kit is 0.6 mg/dL hence if another kit has a

cutoff of more or less than 0.6 mg/dL then the other kit may produce a false positive/negative result accordingly

Check the sensitivity of the another kit with known true CRP calibrator

before confirming the test results

Problem: Positive result with our kit and negative with another kit or vice versa

SLIDE TEST FOR ANTISTREPTOLYSIN O

(RHELAX ASO®)

(Courtesy: Tulip Group of Companies)

Summary

Streptococcus belongs to the family of Lactobacillaceae

and the majority are facultative anerobes. The facultative

anerobic streptococci are divided into two categories:

a.Those which produce soluble hemolysin and

b.Those which do not produce soluble hemolysin

The first group of streptococci are called β-hemolytic

streptococci which can be further subdivided into group

 (a), group (b), group (c) and group (d). It includes most of the

species associated with primary streptococcal infections in

humans. The group (a) β-hemolytic streptococci produce

various exotoxins such as streptolysin O and streptolysin S

that can act as antigens. The affected individuals produce

specific antibodies against streptolysin O, namely anti

streptolysin O (ASO). Determination of these antibodies

is very useful for the diagnosis of streptococcal infections

and their relative effects such as rheumatic fever and acute

glomerulonephritis. An elevated ASO titer of more than

200 IU/mL may indicate an acute streptococcal infection.

Reagent

1. RHELAX ASO reagent: A uniform suspension of

polystyrene latex particles coated with streptolysin

O.

2. Positive control, reactive with RHELAX ASO reagent.

3. Negative control, nonreactive with RHELAX ASO

reagent.

The RHELAX ASO reagent system is standardized to

detect antibodies to streptolysin O in concentrations

ranging from 200 to 4000 IU/mL.

Each batch of reagents undergoes rigorous quality

control at various stages of manufacture for its specificity,

sensitivity and performance.

Reagent Storage and Stability

1. Store the reagent at 2 to 8°C. Do not freeze.

2. The shelf-life of reagent is as per the expiry date

mentioned on the reagent vial labels.

Principle

The RHELAX ASO slide test for detection of antibodies to

streptolysin O is based on the principle of agglutination.

The test specimen (serum) is mixed with RHELAX ASO latex

reagent and allowed to react. If antibodies to streptolysin

O are present in concentrations more than 200 IU/mL,

but less than 4000 lU/mL, then a visible agglutination is

observed. If antibodies to streptolysin O are not present

or are in concentrations less than 200 IU/mL, then no

agglutination will be observed.

Note

1. In vitro diagnostic reagent for laboratory and professional use only. Not for medicinal use.

2. All the reagents derived from human source have

been tested for HBsAg and anti-HIV antibodies and

are found to be non-reactive. However, handle the

material as if infectious.

3. The reagent contains sodium azide 0.1% as preservative.

Avoid contact with skin and mucosa. On disposal,

flush with large quantities of water.

4. The reagent can be damaged due to microbial

contamination or on exposure to extreme temperatures. It is recommended that the performance of

the reagent be verified with the positive and negative

controls provided with the kit.

5. Shake the RHELAX ASO latex reagent well before use

to disperse the latex particles uniformly and improve

test readability.

6. Only a clean and dry glass slide must be used. Clean

the slide with distilled water and wipe dry.

7. Accessories provided with the kit only must be used

for optimum results.

Specimen Collection and Preparation

No special preparation of the patient is required prior to

specimen collection by approved techniques.

Only serum should be used for testing. Should a delay

in testing occur, store the sample at 2 to 8°C. Samples can

be stored for up to a week. Do not use hemolyzed serum.

Material Provided with the Kit

Reagent

RHELAX ASO latex reagent, positive control, negative

control.