Knowledge among clinical personnel on the impact of hemolysis using blood gas analyzers

Clinical impact

Most medical doctors participating in this survey, of whom almost all interpret the analysis results, knew that hemolysis alter the measured potassium concentration. However, only 25.7 % of the medical doctors knew that the blood gas analyzers do not flag for hemolysis. Although most of the respondents (71.8 %) declared to assess the sample quality, this still leaves over 25 % that does not. Furthermore, most of the respondents assessing the sample quality did not look for air bubbles, sample volume or clots before analyzing the sample. Clotting and insufficient volume are well-described preanalytical errors, and bubbles can significantly alter analyte concentrations in blood gas measurements [12]. Thus, even though the respondents declare to assess the quality of the blood samples, this evaluation seems inadequate to reveal all preanalytical errors. Consequently, if the medical doctors responsible for patient’s care are not aware of potential hemolysis and other preanalytical errors, they risk relying on the results released from the instrument, which could lead to erroneous conclusions. Of particular note is the finding that four respondents considered the result valid despite hemolysis if it was released from the instrument. This could be critical and ultimately lead to wrong treatment of the patients. Supporting this, ±8 % of all paired potassium results analyzed on blood gas analyzer and core laboratories in a recent multicenter study were outside the reference change value, indicating a risk of incorrect diagnosis and subsequently incorrect clinical care of the patients in emergency departments [14]. The importance of all these aspects is emphasized by the fact that POCT are used incrementally due to a wish for faster patient flow and a swifter handling of alarming situations – a necessity that increases the importance of a robust and reliable test result: The faster the action, the more important the reliability of the test result upon which the action is based. The increasing use and organizational reliability on POCT result therefore stresses the need for better knowledge about the different caveats and pitfalls in POCT measurements in general.

How to improve

Our study identified a limited knowledge on blood gas analyzers among personnel responsible for blood gas testing and interpretation. This indicates a need for improved education of the personnel handling the blood gas analyzers. The ISO 15189:2022 states that ‘The laboratory shall specify the competence requirements for each function influencing the results of laboratory activities, including requirements for education, qualification, training, re-training, technical knowledge, skills and experience’ and ‘The laboratory shall have a process for managing competence of its personnel, that includes requirements for frequency of competence assessment’ [5]. Furthermore, it is stated that an appropriate theoretical and practical training program for all POCT personnel should be developed and implemented [5]. Managing competences of the personnel handling the blood gas analyzers is however complex as the instruments and the staff performing the POCT measurements primarily are located outside the core laboratories. A well-organized POCT organization and the implementation of user management is a necessity to solve this problem. User management implies education and competence assessment of the relevant staff, which is a huge, but very important task for the laboratories to fulfil. It is crucial that this is supported by the hospital administration and adheres to relevant international guidelines and as of lately the updated ISO 15189:2022, which now has included the POCT area on behalf of the former ISO 22870. In addition, the updated ISO 15189:2022 requires performance of risk assessment. The laboratory is required to identify potential risks to patient care in the pre-examination, examination and post-examination processes. This includes risk assessment of the use of POCT. For this purpose, a risk analysis model to diminish negative impact on patient care by preanalytical errors in blood gas analysis has been proposed [15]. This model is based on identification of errors that may occur while performing blood gas analysis, possible consequences and preventive actions [15].

Another possible improvement area is e-learning and audit as known from the blood sampling area: Willman et al. evaluated a large-scale online e-learning program on venous blood specimen collection with promising results [16]. An e-learning program on blood gas analysis may also improve the whole testing process of blood gasses, including the preanalytical phase and the external staff responsible for these analyses [16]. Another option is the use of an observation scheme or checklist for quality control as suggested for phlebotomy by the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) Working Group for the Preanalytical Phase [17]. Introduction of an observation scheme in blood gas testing may also improve the preanalytical phase in this area. Within the context of improvement, it would be interesting to provide a follow-up survey focusing on the effect of education of POCT users outside of core laboratories.

Today, sample integrity check generally is performed by automated chemistry and immunochemistry equipment in many laboratories. As shown in this survey, some clinicians responsible for interpreting the analysis results are used to lab results without preanalytical flaws (unless clearly stated along with the results), and despite differences in skills of the performing staff, the expectation for flawless results are clearly the same. It is therefore mandatory to consider, how it is technically possible to qualify POCT results besides optimizing the education as mentioned. Casati et al. [10] proposed to introduce automated processing of serum indices in blood gas analyzers, and Buno et al. also stated that technological improvements are desirable [18], as they will ensure that hemolysis, icterus and lipemia does not interfere with the measurements. As an alternative, a photometric hemolysis detection system intended for use with POCT has shown promising results [19]. These are all options that the laboratories need to take into consideration to minimize the risk of decision-making based on erroneous test results.

Strengths and limitations

A limitation of the study is the use of a non-validated questionnaire. However, to our knowledge no validated questionnaire exists in this area. Furthermore, the questionnaire was adjusted and improved in collaboration with members of the Nordic preanalytical scientific working group under NFKK, and finally, the questionnaire was tested on local anesthesiologists to ensure a user-friendly design and appropriate questioning.

As the questionnaire was distributed widely, we have no knowledge about the non-responders. Consequently, we do not know if respondents are representative of the targeted population. However, we have respondents from four Nordic countries indicating the problem to be general and not limited to one hospital or country. The laboratory departments in the Nordic countries are generally well-organized with well-functioning POCT organizations. Furthermore, the hospitals are very similar. Thus, we assume our results to be representative of the hospitals in the Nordic countries. We can only speculate if the results can be extrapolated to other countries, but as stated, many of the observations and challenges are compatible with previous European studies within this area, so our qualified guess is that it can be extrapolated at least to other European countries.