Strategies labs can use to minimize blood draw volumes

Why minimize blood draw volumes?

Minimizing blood draw volumes for patients is critical because repeated phlebotomy can quickly accumulate, leading to significant blood loss over the course of a hospital stay. This loss contributes to hospital-acquired anemia or iatrogenic anemia. Anemia, both at admission and at discharge, is linked with increased complications associated with mortality and readmission rates. It is for these reasons that projects minimizing phlebotomy blood loss can fall into larger hospital quality projects. By optimizing blood draw volumes laboratorians can play a pivotal role in supporting patient safety and quality care initiatives.

What can a laboratory do to reduce blood loss due to phlebotomy?

There are four foundational strategies that laboratories can implement to minimize phlebotomy-related blood loss:

• Use closed blood sampling devices: These systems, such as venous arterial blood management protection systems (VAMPS), return the blood used to clear IV lines back into circulation, significantly reducing wastage.
• Reduce the size of collection tubes: Transitioning from traditional 6-10 mL tubes to smaller vacutainers (2-3.5 mL) or microtainers can substantially decrease the total blood volume drawn.
• Bundle orders for a single collection instance: Coordinating multiple laboratory collections into one blood draw minimizes the number of venipunctures and the cumulative volume of blood collected.
• Point-of-care testing (POCT): While this can reduce laboratory blood draws, it should be reserved for situations that make operational sense and do not overburden clinical staff. As an example, consider respiratory therapists performing blood gas analyses on analyzers available in the intensive care unit (ICU). Adding electrolyte testing on those blood gas analyzers may decrease the need to collect another tube for the main lab.

In our practice, we rely heavily on closed blood sampling devices in the ICU and microtainers for patients who refuse blood products or are stable but severely anemic. While POCT has its place, it should be considered carefully to avoid interfering with patient care and staff efficiency.

Are microtainers the only option?

When we began our blood conservation efforts over 15 years ago, microtainers were the most consistently available option from vendors. Today, the landscape has changed, and vacutainers are now available in smaller sizes (2-3.5 mL). Modern laboratory automation and analytical instruments are also equipped with sensitive liquid level sensors, allowing seamless use of varied tube sizes.

We use microtainers for whole blood hematology and perform offline specimen processing in chemistry followed by a false-bottom tube that is automation ready. Microtainers are 1%-2% of our overall adult inpatient volume and only have a slight impact on turnaround time (for example, the median turnaround time for a complete blood count is now 16 minutes versus 10 minutes).

Where do I start to tackle blood loss due to phlebotomy?

I would start in the acute care setting and assess each patient’s daily blood loss due to laboratory testing. To do this, calculate a daily total blood volume for each patient, which your laboratory information system should be able to help with. Find out how many specimens are collected from lines as well. Hopefully there is a collaborator in nursing or quality, or maybe a transfusion coordinator, that can help with this. If patients consistently lose more than 50 mL daily due to phlebotomy, there is room for improvement. Closed sampling devices should be explored, especially for difficult sticks.

Emily L. Ryan, PhD, DABCC, is a clinical lab director at Advocate Clinical Laboratories and oversees the hospital-based laboratories in Georgia. +Email: [email protected]