IQMH Laboratory Practices for Manual Blood Film Review

Johnston A1, Martin T2,3, Chang H2,4, Olsen B2,5, Leung E2,6, Moffat 2,7K , Good D2,8 1Institute for Quality Management in Healthcare, Toronto, ON, Canada; 2Institute for Quality Management in Healthcare Hematology Scientific; Committee, Toronto, ON, Canada;3 Health Sciences North/Horizon Santé- Nord, Sudbury, ON, Canada; 4University Health Network, Toronto, ON, Canada; 5William Osler Health System, Brampton, ON, Canada; 6Division of Haematology and Transfusion Medicine Children’s Hospital of Eastern Ontario University of Ottawa, Ottawa, ON, Canada; 7Hamilton Regional Laboratory Medicine Program, Hamilton, ON, Canada; 8Department of Pathology and Molecular Medicine, Queen’s University, Kingston, ON, Canada

INTRODUCTION Figure 1. Types of facilities

Microscopic examination of a blood film is the second most common hematology test, after the complete blood count (CBC). Interpretation of a well-prepared and stained blood film by trained laboratory professionals provides valuable diagnostic information.1,2 The Institute for Quality Management in Healthcare (IQMH) Hematology Scientific Committee developed a detailed survey to gather information regarding current practices for manual blood film review and reporting from provincial laboratories participating in IQMH blood film morphology proficiency testing surveys.

METHODS

In November 2017, a patterns-of-practice survey was distributed to 174 laboratories participating in the IQMH Morphology program. The survey consisted of 24 questions that related to individual laboratory practices for manual blood film review. “Manual blood film review” was defined as blood films microscopically reviewed by either a medical laboratory technologist or a laboratory physician.

RESULTS

One hundred sixty-nine participants submitted results with a response rate of 97%. Presented here is a summary of the responses: Types of Facilities Figure 2. Specialized services supported by laboratories Eighty-two per cent of participants were laboratories affiliated with small- or medium-sized hospitals with less than 500 beds. Eight per cent indicated a large hospital, 7% a community laboratory and 3% “other”, which included outpatient, a trauma hospital and an urgent care centre (Figure 1). Specialized Services Supported by Laboratories Laboratories were asked to indicate the specialized services they supported (Figure 2) in order to ascertain the complexity of peripheral blood morphology encountered at a participant’s site. Digital Imaging The majority (86%) of laboratories do not use digital imaging for initial blood film review. Of the 14% that do, most (91%) use CellaVision (Sweden) and the remaining 9% use the Sysmex (Japan) DI-60 system. Technologists that Perform Manual Blood Film Review Percentage of blood films reviewed by a technologist and physician, by facility, is summarized in Figure 3. • 80% of respondents stated core laboratory technologists perform manual blood film reviews, while only 2% utilized hematology technologists with morphology expertise. Results of this survey indicated very few laboratories have dedicated morphology technologists. • All respondents had a policy for manual blood film review by a technologist. Seventy per cent did not have blood films reviewed by a senior or charge technologist prior to review by a physician. • 83% send 0%–5% of daily blood films for physician review after the film was reviewed by a technologist. Critical Results The majority (88%) of participants included morphological findings in their critical result list. For the purposes of this patterns-of-practice survey, a “critical result” is considered a finding/result that requires prompt notification of an ordering physician because the result may require rapid clinical Figure 3. Blood film review by technologist and physician by facility attention to avert patient morbidity or mortality. Of the 148 participants that reported that they included morphological findings in their critical list, most (98%) included malaria, and the majority (88%) included the first time presence of blasts (Table 1). Table 1. Included in Critical Result List (n=148) Included in Critical Result List No. of Labs % of Labs 1st time presence of blasts 130 88 Malaria 146 99 Circulating plasma cells 28 19 Blood film showing schistocytes in context of thrombocytopenia 66 45 Presence of abnormal promyelocytes 52 35 Sickle cells 60 41 Intracellular/extracellular bacteria 74 50 Other 16 11 • 59% of participants had a procedure to ensure that interpretation and confirmation of first time potentially significant morphological findings are available from a physician at all times. • 56% of laboratories indicated they would report blast cells as a first time finding without requiring confirmation from a physician. Other Reporting Practices • 77% of participants reported band cells separately from mature neutrophils in the CBC differential count. Other reporting practices can be seen in Tables 2 and 3. Table 2. Lab Policy for Reporting Abnormal and Reactive Lymphocytes by the CONCLUSIONS Technologist (n=169) Even with major diagnostic advances in hematology, morphological blood film examination is still No. of Labs % of Labs Count abnormal lymphocytes in a separate category 75 44 a valuable tool. It is often the first window into a patient’s disorder, providing important diagnostic Count reactive lymphocytes in a separate category 97 57 information and guiding subsequent testing. Ensuring proficiency in this skill should remain a priority Include reactive lymphocytes with lymphocytes and include a for hematology laboratories. 70 41 descriptive comment The overall results from our survey showed considerable variation in laboratories’ practices for manual Include abnormal lymphocytes with lymphocytes and include a 73 43 blood film review and reporting. descriptive comment Laboratories must ensure urgent cases are reviewed and reported promptly to avoid diagnostic and The question did not specifically ascertain whether the descriptive comment was being made by the treatment delays. These patterns-of-practice survey results will be used to develop IQMH guidelines for technologist or the laboratory physician. manual blood film review and reporting. Table 3. Policy for Technologist Reporting Questionable Blasts (n=169) Policy for reporting questionable blasts No. of Labs % of Labs Count as blasts 50 30 References Count as “other” or “unidentified” 28 16 Count as “other” or unidentified with a qualifying description 91 54 1. Gulati G, Song J, Florea AD, Gong J. Purpose and criteria for blood smear scan, blood smear examination, and blood smear review. Ann Lab Med. 2013 Jan; 33(1):1–7. Comment: Over half (54%) of the participants’ laboratory policy for reporting questionable blasts is to count as “other” or unidentified with a qualifying description. 2. Bain BJ. Diagnosis from the blood smear. N Engl J Med. 2005 Aug4; 353(5):498–507.