According to the journal presented by Neuwinger, Büschenfelde, and Kappert (2019), lactate dehydrogenase activity can falsely increase because of underfilling the blood specimen tube. Stated in the discussion part, "test results obtained in underfilled blood tubes should be communicated by the diagnostic laboratory with an attached comment pointing to the possibility of a falsely elevated test result". My question is derived from the mentioned part of the journal:
Should a medical laboratory scientist be in the situation of underfilling a blood specimen, what proper solution or protocol must be applied? Would the researcher's recommendation suffice?
According to CLSI's Procedures for handling, transport, and processing of blood specimens for common laboratory Tests (1st ed.), the criteria for rejecting underfilled specimens may vary depending on the tube and the test requested. Therefore, they recommend not to immediately reject specimens but to investigate these criteria. This is not limited to filling of tubes but other factors as well.
As for the study by Neuwinger et al., their recommendation is sufficient as a post-analytical response. However, it is only proper that the laboratory ensures that their protocol includes taking all measures to collect the sufficient amount of blood and that their medical laboratory scientist is following this. In doing so, the unexpected causes of underfilling/overfilling can be narrowed down which helps in achieving accurate results for the patient's benefit.
The journal article "Underfilling of vacuum blood collection tubes leads to increased lactate dehydrogenase activity in serum and heparin plasma samples" by Neuwinger et al. (2020) doesn't outline a specific standard protocol for underfilled tubes. However, based on the findings of the study, common practices likely involve:
- Flagging Test Results: Laboratories likely flag test results from underfilled tubes to alert healthcare providers about potential inaccuracies, especially for lactate dehydrogenase (LDH) levels.
- Communication: This information is then communicated to the requesting physician, often through comments attached to the test results or a direct notification.
- Clinical Consideration: With this knowledge, the healthcare provider can interpret the test results while considering the possibility of altered values due to underfilling. Depending on the situation, a retest using a properly filled tube might be requested.
This approach ensures awareness of potential issues with underfilled tubes and allows for informed interpretation of test results.
According to Center for Phlebotomy Education (n.d.), sending tubes to the lab that are not adequately filled could lead to inaccurate test results and misguide physicians, potentially causing patients to receive incorrect medication or diagnosis. To increase the likelihood of identifying the bacteria causing bacteremia, it's crucial to collect a sufficient amount of blood for a culture. If less than 20cc of blood is collected from an adult patient, it's recommended to fill the aerobic vial with the maximum volume rather than splitting smaller amounts between two vials. Since most septicemias are caused by aerobic organisms or facultative anaerobes, it's important to prioritize aerobic vials. About 16% of unacceptable specimens are reported to be underfilled, so healthcare workers responsible for specimen collection should always have smaller volume tubes on hand to ensure specimen integrity and accurate results, especially when draws don't go as planned.
Reference:
Center for Phlebotomy Education (n.d.) Underfilling Tubes. Retrieved from https://www.phlebotomy.com/underfilling-tubes.html