Descripción
C Reactive Protein (CRP) (Latex)
A rapid latex slide test for the
detection of CRP in serum
REF: 514 000 50 test (Complete Kit)
REF: 514 001 100 test (Complete Kit)
REF: 514 002 50 test (latex with positive control)
REF: 514 003 100 test (latex with positive control)
REF: 514 004 50 test (latex only)
REF: 514 005 100 test (latex only)
Intended Use
Rapid latex agglutination test for the qualitative screening and semiquantitative determination of C Reactive Protein (CRP) in human
serum.
Deterioration
Latex reagent has a white uniform appearance after shaking ,reagent
should be discarded in case of visible clumping.Do not use the latex
reagent or controls in case of contamination.
Background
In infections caused by ß-hemolytic streptococci, Streptolysin O is liberated from the bacteria stimulating production of antistreptolysin O (ASO) antibodies. The extent and degree of the infection can be monitored by measuring the levels of these antibodies. Increase in ASO titre generally occurs one to four weeks after onset of infection with
-hemolytic streptococci Group A. As the infection subsides, the titre declines and returns to normal levels within six months. If the titre does not decrease, a recurrent or chronic infection may exist.
Specimen Collection and Preservation
Use only serum specimens , plasma samples are not suitable for the test. Serum samples can be stored for 24 hrs at 2 – 8oC, for longer storage it is recommended to store the samples at -20oC.
Test Principle
Spectrum CRP latex reagent is a suspension of polystyrene particles sensitized with anti-human CRP. When the latex reagent is mixed with a serum containing C-reactive protein, visible agglutination occurs. The latex reagent has been produced so that agglutination will take place only when the level of CRP is greater than 6 mg/L.
Reagents
Spectrum CRP latex kit contains the following reagents:
Latex Reagent :
A suspension of polystyrene latex particles in glycine-saline buffer
pH: 8.6 ± 0.1, coated with anti-human CRP antibodies.
Positive Control Serum (bottle with red cap):
Is prepared from a stabilized human serum pool containing CRP as an antigen.
Both reagents contain 0.9 g/L Sodium azide as a preservative.
Negative Control Serum (bottle with white cap):
Reagent contain 0.9 g/L Na azide as a preservative.
Slides
Note: Negative Control Serum and Slides are only included in
Complete Kits REF: 514 000 (50 test) and REF: 514 001 (100 test).
Precautions and Warnings
All human blood components used to prepare controls have been
tested for Hepatitis B surface antigen (HBsAg) and HTLV-III antibodies
by FDA approved procedure and found to be non-reactive
No known test method for HBsAg or HTLV-III antibodies offers total
assurance that a human derived product will not transmit hepatitis
or HTLV-III virus. The user is therefore cautioned to handle reagents
as if being capable of transmitting these diseases.
Storage and Stability
The reagents are stable up to the expiration date stated on the label when stored at 2 – 8 oC.Open vials are stable for 6 months at the specified temperature.
Procedure
Qualitative Test (Screening)
1. Bring all reagents and specimens to room temperature.
2. Place one drop (50 l) of the positive control and 50 l of the patient serum into separate circles on the glass slide.
3. Shake the CRP latex reagent gently and add one drop (45 l) on each circle next to the sample to be tested and control.
4. Mix well using disposable stirrer spreading the mixture over the whole test area and tilt the slide gently. Agitate for about 2 minutes with rotator or by hand and observe for the presence or abscence of agglutination.
Results and Interpretation
Negative result: No agglutination of the latex particles suspension
within two minutes.
Positive result: An agglutination of the latex particles suspension
will occur within two minutes, indicating a CRP level of more than
6 mg/L.
Semi-Quantitative Test
1. Serum to be titrated is serially diluted (1:2, 1:4, 1:8 etc) in 0.9 g/L
saline solution.
2. Place one drop of positive control on slide. Do not attempt to dilute
the CRP positive control serum for comparative or other purposes
as no correlation exists between actual titre of the control and titre
of unknown sera.
3. Place 50 l of each serum dilution individually in successive circles
on the slide and proceed as in screening methodology
Results and Interpretation
The serum CRP titre can be defined as the highest dilution showing
a positive result. The approximate CRP level ( mg/L) present in the
sample can be optained by the following formula:
CRP Titre ( mg/L) = Highest dilution with positive reaction x
Reagent sensitivity ( 6 mg/lL)
e.g. if the agglutination is present up to a titre 1:8, the approximate
serum CRP level is 8 x 6 = 48 mg/L.
Expected Value
Up to 6 – 8 mg/L.
Limitations of the Procedure
Occasional agglutinations observed after 4 minutes have no diagnostic
significance.
Highly haemolyzed and lipemic serum as well as plasma interfere
with the test.
Performance charcteristics
1. Analytical sensitivity: 6 (5-10) mg/L, under the described assay
conditions.
2. Prozone effect: No prozone effect was detected up to 1600 mg/L.
3. Diagnostic sensitivity: 95.6 %.
4. Diagnostic specificity: 96.2 %.
Interfering Substances
Haemolysis
No significant interference from haemoglobin up to 10 g/dL.
lcterus
No significant interference from free and conjugated bilirubin up to
levels of 20 mg/dL
lipemia
No significant interference up to levels of 10 g/dL
Rheumatoid factor
No significant interference up to 300 IU/ml
Waste Disposal
This product is made to be used in professional laboratories.
Please consult local regulations for a correct waste disposal.
S56: dispose of this material and its container at hazardous or
special waste collection point.
S57: use appropriate container to avoid environmental contamination.
S61: avoid release in environment. refer to special instructions/safety
data sheets.
References
1. Bowman BH. In:Hepatic Plasma Protein. San Diego: Academic
Press;1993:47-95.
2. Halbert, SP. Ann. N.Y. Acad. Sci., 103, 1027:1051; 1963.
3. Klein GL, Applied Microbiology, 21:999, 1971.
4. Klein GC: Manual of Clinical Immunology ASM 264-273: 1976.
5. Pepys MB et al. Lancet 1961 ; 1 : 653-660.
6. Rantz LD, DiCapri JM, Randall E. Am. J. Med. Sci., 24, 1952
