C-reactive protein (CRP) is a protein made by the liver. CRP levels in the blood increase when there is a condition causing inflammation somewhere in the body. A CRP test measures the amount of CRP in the blood to detect inflammation due to acute conditions or to monitor the severity of disease in chronic conditions.

1. Jan 2021
Subject Name : Advanced Clinical Chemistry
Topic : Immunological Test [ C-Reactive Protein (CRP) ]

2. C-Reactive Protein (CRP)
C-reactive protein (CRP) is a protein made by the liver. CRP levels in
the blood increase when there is a condition causing inflammation
somewhere in the body. A CRP test measures the amount of CRP in
the blood to detect inflammation due to acute conditions or to
monitor the severity of disease in chronic conditions.
CRP is a non-specific indicator of inflammation and one of the most
sensitive acute phase reactants. That means that it is released into the
blood within a few hours after an injury, the start of an infection, or
other cause of inflammation. Markedly increased levels can occur, for
example, after trauma or a heart attack, with active or untreated
autoimmune disorders, and with serious bacterial infections, such as
in sepsis.

3. Why Get Tested?
To identify the presence of inflammation and to monitor response to
treatment for an inflammatory disorder.
Sample Required?
A blood sample taken from a vein
Test Preparation Needed?
None

4. How is the test used?
The C-reactive protein (CRP) test is used to detect inflammation.
For example, CRP may be used to detect or monitor significant
inflammation in acute conditions, such as:
A serious bacterial infection of the lung, urinary tract, digestive tract,
skin, or other sites, with or without sepsis
A fungal or viral infection
Autoimmune diseases
The CRP test may be used to monitor patients after surgery.
Generally, CRP levels increase after surgery and drop down to normal
unless post-surgery infection is present.
CRP can be a good predictor of rejection in kidney transplant
recipients.

5. What does the test result mean?
The level of CRP in the blood is normally low.
Increased CRP level:
A high or increasing amount of CRP in the blood suggests the
presence of inflammation but will not identify its location or the
cause.
Suspected bacterial infection—a high CRP level can provide
confirmation that you have a serious bacterial infection.
If the CRP level is initially elevated and drops, it means that the
inflammation or infection is subsiding and/or responding to
treatment.

6. What is the difference between CRP and hs-CRP tests?
Both tests are essentially the same, measuring the same substance in
the blood. However, the high sensitivity CRP (hs-CRP) test measures
very small amounts of CRP in the blood and is ordered most frequently
for seemingly healthy people to assess their potential risk for heart
problems. It typically measures CRP in the range from 0.3 to 10 mg/L.
The regular CRP test is ordered for those at risk for infections or
chronic inflammatory diseases (see above). It measures CRP in the
range from 8 to 1000 mg/L (or 0.8 to 100 mg/dL).

7. procedure of the CRP :
1. All solutions and patient serum (Serum) are prepared at room
temperature.
50 μl of Positive Control are placed in the first circle on the latex slide
and 50 μl of Negative Control in the second circle, in order to make a
comparison after the results have come out and to ensure the
viability of the solutions.
3. 50 μL of patient Serum are placed in the third circle on the latex
slide.
4. shake the latex vial gently and add 50 μl of latex solution (1 drop) to
Positive Control, Negative Control, and Serum of the patient.
5. Mix in a circular motion using appropriate sticks.
6. The latex slide is placed on the Shaker vibrator for 1-3 minutes.
Stacking appears under the light.

9. No result is taken after this time because it begins to dry out the
samples, which may lead to Positive False.
• (+): Agglutination (Ab-Ag Reaction) agglutination.
(-): Non Agglutination (Ab-Ag Non Reaction) does not occur.
A picture of CRP joints when stacking is present and when stacking is
not present.
If agglutination has occurred, dilution is applied to give a numerical
result

10. Semiquantitative Slide Test
If a positive reaction is obtained, the specimen may be serially diluted
with glycerine-saline buffer to obtain a semiquantitative estimate of
the CRP level.
Begin with a 1:2 dilution of patient's serum obtained by equal volumes
of specimen and glycerine-saline buffer. Blend the tube content
thoroughly.
Add 100uL of buffer to the desired numbers of tubes.
Add 100uL of the 1:2 dilution to the first tube; mix and transfer 100uL
to the next additional tube. Continue untill all tubes are diluted.
Discard last 100uL from the last tube.