American Society for Clinical Pathology (ASCP) Histotechnician Certification Practice Exam

What is the correct procedure for collecting blood from an indwelling line?

1. To collect the first 5 mL and discard

2. To discard the first 5 mL

3. To use a syringe for collection

4. To collect the last 5 mL and keep

The correct answer is: To discard the first 5 mL

The correct procedure for collecting blood from an indwelling line involves discarding the first 5 mL of blood. This step is crucial because the initial blood collected from an indwelling catheter may contain non-representative samples due to potential contamination from the catheter or the fluid that has been infused into the line. By discarding this initial volume, you help ensure that the blood sample collected is more reflective of the patient's actual blood composition and reduces the risk of introducing contaminants into the sample. This practice is especially important for accurate laboratory results, as any contaminants can alter blood parameters and lead to misinterpretation of the patient’s clinical status. The procedure emphasizes the importance of proper sampling techniques to ensure diagnostic accuracy and patient safety.