Pipetting is a fundamental laboratory skill, and when handling blood samples, precision and accuracy are crucial to obtaining reliable results. Here are some good pipetting techniques when dealing with blood samples:
Choose the Right Pipette and Tip:
Ensure the pipette is appropriate for the volume you're transferring.
Use a fresh tip for each sample to prevent cross-contamination.
Pre-Wetting the Pipette Tip:
Especially for small volumes, aspirate and expel the sample a couple of times before taking up the volume you intend to transfer. This ensures the air inside the pipette tip is saturated with the liquid, improving accuracy.
Aspirate Slowly and Smoothly:
Avoid rapid aspiration, which can create bubbles or lead to imprecise volumes.
Maintain a Consistent Angle:
Hold the pipette vertically (at a 90° angle) when aspirating the sample. When dispensing into a tube or well, a slight angle (e.g., 45°) is often recommended.
Avoid Immersing the Tip Too Deeply:
Only immerse the very tip of the pipette into the blood sample to avoid taking up more than needed.
Eliminate Air Bubbles:
Ensure there are no air bubbles in the pipette tip after aspirating. If bubbles are present, dispense the sample and start again.
After dispensing the blood, touch the pipette tip to the side of the receiving vessel to remove any remaining droplets.
Pause After Aspiration:
Wait for a second after you've aspirated the liquid and before you begin to dispense to ensure you've drawn up the full amount.
Practice Proper Ergonomics:
Maintain a relaxed posture and grip. Continuous pipetting can lead to repetitive strain injuries if not done with care.
Ensure pipettes are calibrated regularly to maintain accuracy.
When pipetting blood samples, ensure that the outer part of the pipette tip doesn't touch any surfaces. Any contamination can alter test results or introduce errors.
Always store pipettes in an upright position after use.
Cleaning and Maintenance:
Pipettes should be cleaned regularly, and any spills, especially of biohazardous material like blood, should be immediately cleaned according to lab safety protocols.
Remember that while good technique is essential, consistent practice is necessary to maintain proficiency in pipetting. Regular training and routine checks can help ensure that technicians remain skilled in this fundamental lab technique.