Blood Collection in the Laboratory
Blood collection, also known as phlebotomy, is a crucial step in medical diagnostics. Proper Venipuncture ensures accurate laboratory results, aiding in the diagnosis, monitoring, and treatment of various medical conditions.
Purpose of Venipuncture
- To diagnose diseases by analyzing blood components.
- To monitor ongoing treatment or the progression of a disease.
- To evaluate organ function, such as liver or kidney health.
Steps in Blood Collection
| Step | Details |
|---|---|
| 1. Preparation of Patient | Verify patient identity, explain the procedure, and ensure they are calm and relaxed. |
| 2. Selection of Site | Identify a suitable vein, usually in the arm (e.g., median cubital vein). |
| 3. Preparation of Equipment | Gather necessary items like a tourniquet, syringe, needle, blood collection tubes, and antiseptic. |
| 4. Aseptic Technique | Clean the puncture site with an antiseptic solution to prevent contamination. |
| 5. Venipuncture | Insert the needle into the vein and collect the required amount of blood into appropriate tubes. |
| 6. Post-Collection Care | Remove the needle, apply pressure to stop bleeding, and cover with a sterile bandage. |
Types of Blood Samples Collected
- Whole Blood: Used for complete blood count (CBC) and blood typing.
- Plasma: Collected in tubes with anticoagulants for tests like coagulation studies.
- Serum: Obtained from clotted blood for biochemical tests like liver or kidney function tests.
Common Blood Collection Tubes and Their Uses
| Tube Color | Additive | Purpose |
|---|---|---|
| Purple/Lavender | EDTA | Complete blood count (CBC), and blood smears. |
| Blue | Sodium citrate | Coagulation studies (e.g., PT, APTT). |
| Red | No additive (clot activator) | Serum biochemistry, hormone levels. |
| Green | Heparin | Plasma for biochemistry tests. |
| Yellow | Gel separator with clot activator | Serum for immunology and serology. |
Precautions During Blood Collection
- Ensure proper patient identification to avoid errors.
- Use sterile equipment to prevent infections.
- Follow the correct order of draw to avoid cross-contamination of additives between tubes.
- Avoid prolonged tourniquet application to prevent hemoconcentration.
Complications of Blood Collection
- Hematoma Formation: Bruising due to blood leakage at the puncture site.
- Infection: Rare, but possible if aseptic techniques are not followed.
- Fainting: Some patients may feel dizzy or faint during the procedure.
Conclusion
Blood collection is a critical procedure in clinical diagnostics.
Following proper techniques and precautions ensures safe sample collection and reliable test results, contributing to accurate diagnoses and effective treatment.