Principle
Rheumatoid factor
latex test kit consists of polystyrene latex particle coated with specially
modified preparation of human gammaglobulin (IgG) in order to avoid non
specific agglutination.
The suspension of
coated latex particles agglutinate visible when mixed with serum containing
rheumatoid factor. The sensitivity of reagent has been adjusted to
detect=10IU/ml of RF calibrated against an international standard.
Specimen: Use
fresh serum specimen
Requirements
- Latex reagent
- Positive control
- Negative control
- Glass slide
- Disposable
applicator stick
- Disposable plastic
dropper
- Rubber teats
Procedure
A. Qualitative method:
- Bring all reagent as
well as the samples at room temperature (+15°C to +30°C).
- Using the disposable
plastic dropper, place one drop of test serum within the circled area
marked TEST on the special slide
provided in the kit.
- Shake the vial
gently and add one drop of latex gammaglobulin reagent (using the dropper
provided in vial Cap =40μl) to the
above drop and mix well with a disposable applicator stick.
- Rock the slide gently to and for 2 minutes&examine for agglutination.
- Do not examine beyond
2 minutes.
Result
Result should be
read within 2 minutes.
Clearly visible agglutination indicates a positive granularity of doubtful clumping should be ignored
B. Semi Quantitative method
To determine the titer (i.e. the highest
dilution showing visible agglutination prepare serial doubling test serum using normal saline, from 1:2
doubling up to 1:128 or as needed.
- Place one drop of each dilution of serum
within the respective marked area of special slide in the kit.
- Add one drop of thoroughly mixed latex
gammaglobulin reagent and mix well with disposable applicator stick. Use separate stick for each
serum dilution.
- Gently rock the
slide to and fro and observe agglutination for no longer than 2 minutes.
Absent in cases
of rheumatic fever. The latex
agglutination test does not provide the final diagnosis of n rheumatoid arthritis. And therefore, it
should be used only in conjunction with proper clinical evaluation.
Observation
A. Qualitative test
Result
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B. Semi-quantitative test:
Result
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Conclusion
Clinical significance: Because of the delayed appearance of
the rheumatoid factor (RF), it is more frequently present in chronic active
phases of the disease than in the early or in the sub-clinical chronic phases
of rheumatoid arthritis.
Rf is also found in many cases of autoimmune diseases like
systematic Lupus erythematosus (SLE), scleroderma and Sjogren’s syndrome,
weekly positive latex Agglutination test for rheumatoid factor has occasionally
been observed in some sera of patients with Hepatitis, Sarcoidosis, Cirrhosis
of liver, Syphilis, Hypergammaglobulinemia, acute bacterial and viral
infection.
Reference
KIT USED-ARKRAY HEALTHCARE PVT.LTD
RHEUMATOID ARTHRITIS (RF) LATEX TEST.
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