Total Leukocyte Count

Allied Guru

Principle

Total Leukocyte Count (TLC) ek diagnostic test hai jisme blood sample mein white blood cells (WBCs) ki total quantity measure ki jaati hai. WBCs, ya leukocytes, immune system ka important part hote hain aur unka count infection, inflammation, aur doosre health conditions ko indicate karta hai.

  • Test ka principle yeh hai ki blood sample ko ek reagent se dilute kiya jaata hai jo red blood cells (RBCs) ko tod dega, lekin WBCs intact rahenge.

  • Uske baad WBCs ko microscope ke under ek specific area mein count kiya jaata hai, chahe manually hemocytometer ka use karke ya automated cell counter se.

  • Yeh test fresh blood sample pe kiya jaata hai, taaki cells ka count accurate rahe.

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Requirements

  1. Blood Sample:

    • Blood fresh hona chahiye, kyunki stored blood se WBC count galat ho sakta hai.

    • Venous blood sample liya jaata hai for accurate results.

  2. Dilution Fluid:

    • Ek diluent use kiya jaata hai blood sample ko dilute karne ke liye aur RBCs ko lyse karne ke liye. Common diluents hain:

      • Acetic acid: Yeh RBCs ko todta hai, lekin WBCs ko intact rakhta hai.

      • Turk’s solution: Acetic acid, gentian violet (dye) aur kabhi-kabhi distilled water ka mix hota hai, jo WBCs ko dikhne mein madad karta hai.

      • Hayem’s solution: Ek aur solution jo blood ko dilute karne ke liye use hota hai.

  3. Hemocytometer:

    • Ek specialized glass slide hota hai jisme grid hoti hai, jo microscope ke under cells ko count karne mein help karta hai. Hemocytometer chamber ek fixed volume of liquid hold karta hai, taaki cell concentration calculate kiya ja sake.

  4. Microscope:

    • Ek achha microscope (usually 400x magnification ya usse zyada) chahiye hota hai taaki cells ko clearly dekha ja sake.

  5. Coverslip:

    • Ek thin glass cover jo hemocytometer ke upar rakha jaata hai taaki sample move na ho aur easily examine kiya ja sake.

  6. Pipettes:

    • Precise pipettes use kiye jaate hain blood aur diluting fluid ko hemocytometer par transfer karne ke liye.

  7. Timer:

    • Ek timer use karte hain taaki blood dilution ke baad RBCs ko properly lyse hone ka time mile aur WBCs count karne mein accuracy ho.

 

Procedure

  1. Blood Sample Preparation:

    • Fresh venous blood ek sterile technique se collect karna hota hai.

    • Blood ko ek diluent (e.g., Turk’s solution) ke saath test tube mein mix karte hain. Common ratio 1 part blood to 20-100 parts diluent hota hai, method ke hisaab se.

    • Mixture ko 2-5 minutes ke liye chhod dete hain, taaki RBCs properly lyse ho jaayein aur WBCs intact rahen.

  2. Loading the Hemocytometer:

    • RBCs lyse hone ke baad, mixture ko gently mix karte hain taaki WBCs evenly suspended ho jaayein.

    • Pipette ki madad se diluted sample ek drop ke form mein hemocytometer par rakhte hain.

    • Coverslip ko properly place karte hain taaki fluid evenly spread ho jaye.

  3. Microscopic Examination:

    • Hemocytometer ko microscope ke under rakhte hain.

    • 400x magnification (ya zyada agar zaroorat ho) par focus karte hain.

    • WBCs usually larger, round cells hote hain jisme prominent nucleus hota hai, jo RBCs se easily distinguish ho jaate hain. Agar Turk’s solution use ho toh WBCs thoda colored dikhte hain.

  4. Counting the Cells:

    • Manual counting mein, hemocytometer ke defined area (generally 4 large squares) mein WBCs ko count karte hain.

    • Har square ek specific area cover karta hai, aur kai squares mein count karne par representative result milta hai.

  5. Calculation of WBC Count:

    • WBC count ko calculate karne ke liye formula use hota hai:

      TLC (cells/mm³) = (Total WBC count in counted area/Area of counted grid)×Dilution Factor

    • Agar automated counter ho, toh yeh calculation automatically ho jaata hai.

  6. Record the Result:

    • Result ko usually WBCs per cubic millimeter (cells/mm³) ke form mein report kiya jaata hai.

Clinical Significance

TLC test kaafi important diagnostic tool hai jo kai clinical situations mein use hota hai. WBCs ke abnormal levels alag-alag diseases ko indicate karte hain.

  1. Leukocytosis (Elevated WBC Count):

    • High TLC ka matlab ho sakta hai:

      • Infections: Jaise bacterial infections, jisme body zyada WBCs produce karti hai infection se ladne ke liye.

      • Inflammation: Conditions jaise rheumatoid arthritis, allergies, autoimmune disorders mein WBC count badh jaata hai.

      • Leukemia: Blood cancer, jo white blood cells ke abnormal production ko cause karta hai.

      • Stress or trauma: Physical stress ya tissue damage ke response mein WBCs badhte hain.

      • Drug-induced: Kuch medications (e.g., corticosteroids) WBC count ko increase karte hain.

  2. Leukopenia (Decreased WBC Count):

    • Low TLC indicate kar sakta hai:

      • Bone marrow disorders: Conditions jaise aplastic anemia ya myelodysplastic syndromes jo WBC production ko affect karte hain.

      • Viral infections: Kuch viral infections (e.g., HIV, hepatitis) WBC production ko suppress kar sakte hain.

      • Autoimmune diseases: Jaise lupus, jo WBCs ko reduce karte hain.

      • Chemotherapy or radiation therapy: Yeh treatments bone marrow ko affect karte hain aur WBCs ki production ko kam karte hain.

      • Nutritional deficiencies: Vitamin B12, folic acid, ya copper ki kami WBCs ko kam kar sakti hai.

  3. Other Clinical Considerations:

    • Neutrophilia: Neutrophils ka increase bacterial infections, inflammation, ya tissue damage mein hota hai.

    • Lymphocytosis: Lymphocytes ka increase viral infections ya lymphocytic leukemia mein hota hai.

    • Monocytosis: Monocytes ka increase chronic infections ya inflammatory conditions mein dekha jaata hai.