What is the Full Form of CFT?
CFT stands for Complement Fixation Test. It is a serological test used to detect the presence of specific antibodies in a patient's blood by assessing complement system activation. CFT is commonly used for diagnosing infections such as syphilis, tuberculosis, and viral diseases. Though less commonly used today due to advanced diagnostic methods like ELISA, CFT remains important in some medical and research applications.
Principle of Complement Fixation Test (CFT)
The Complement Fixation Test (CFT) is based on the principle that when an antigen-antibody reaction occurs, the complement system (a group of proteins in the blood) gets activated and "fixed" to the immune complex. If the complement is consumed in this reaction, it will not be available to lyse red blood cells in a secondary reaction.
Positive Test: If antibodies are present in the patient’s serum, the complement is fixed, and no hemolysis occurs.
Negative Test: If no specific antibodies are present, the complement remains free and causes hemolysis of red blood cells in the indicator system.
This test is useful for diagnosing bacterial, viral, fungal, and parasitic infections by detecting specific antibodies in the serum.
Process of Complement Fixation Test (CFT) in Short
Serum Preparation – The patient’s serum is heated to inactivate the natural complement.
Antigen Addition – A specific antigen is added to the serum.
Complement Addition – Standard complement proteins are introduced.
Incubation – The mixture is incubated at 37°C for 1 hour for the reaction.
Indicator System – Sensitized sheep RBCs and hemolysin are added.
Result Interpretation:
No Hemolysis (Positive Test) – Antibodies present, complement is fixed.
Hemolysis (Negative Test) – No antibodies, free complement lyses RBCs.
Used for diagnosing infections like syphilis, tuberculosis, and viral diseases.
Advantages of Complement Fixation Test (CFT)
High Sensitivity – Detects even low levels of specific antibodies in the serum.
Wide Application – Useful for diagnosing bacterial, viral, fungal, and parasitic infections.
Early Disease Detection – Helps identify infections in their early stages before symptoms appear.
Cost-Effective – Relatively inexpensive compared to advanced molecular diagnostic tests.
Conclusion:
The Complement Fixation Test (CFT) is a valuable serological test for detecting infections by identifying specific antibodies. Its sensitivity, broad application, and cost-effectiveness make it useful in diagnosing bacterial, viral, and parasitic diseases. Though modern techniques like ELISA have replaced it in many cases, CFT remains important in certain diagnostic settings.
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FAQs on CFT Full Form
1. What is the Full Form of CFT?
CFT stands for Complement Fixation Test, a serological test used to detect specific antibodies in a patient’s serum.
2. What is the Purpose of the Complement Fixation Test?
CFT is used to diagnose infections like syphilis, tuberculosis, and viral diseases by detecting antigen-antibody reactions.
3. How Does the Complement Fixation Test Work?
It works by checking whether the complement proteins get fixed in an antigen-antibody reaction, preventing red blood cell hemolysis.
4. What Are the Steps in the CFT Process?
CFT involves serum preparation, antigen and complement addition, incubation, and an indicator system using sensitized RBCs.
5. Is the Complement Fixation Test Still Used Today?
While ELISA and PCR have replaced CFT in many cases, it is still used in specific diagnostic applications.
6. What Are the Advantages of CFT?
CFT is highly sensitive, cost-effective, useful for early disease detection, and applicable for various infections.
7. What Diseases Can Be Diagnosed Using CFT?
CFT is used to detect syphilis, tuberculosis, viral infections, fungal diseases, and some parasitic infections.
8. What are the Limitations of CFT?
CFT requires trained personnel, careful handling, and may give false-positive or false-negative results in some cases.
9. Is CFT Used for COVID-19 Testing?
No, COVID-19 testing primarily relies on RT-PCR and ELISA-based antibody tests, rather than CFT.
10. Where Can I Learn More About CFT for NEET Preparation?
For detailed explanations and NEET 2025 study material, check out Vedantu’s comprehensive resources to boost your exam preparation.
