Quality Principles in Blood Film Reporting
Blood film reporting is both a science and an art. Understanding some basic principles can help ensure that our reports are of high quality and provide significant value to patient care. It is a meticulous process involving detailed examination of blood cells under a microscope. It requires combining scientific knowledge, technical skills, and an intuitive understanding of haematological abnormalities. The goal is to provide a comprehensive analysis that can aid in diagnosing various conditions, from infections to haematological malignancies.
Following some general principles (Figure 5.10), you can build a foundation for implementing rigorous standards, maintaining consistency, and ensuring the highest quality in your blood film reports. This will ultimately enhance patient outcomes and advance clinical care.
Reliability
Reliability in blood film reporting is crucial for accurately identifying abnormalities and avoiding false results. Ensuring that reports are reliable means that healthcare providers can trust the findings and make informed decisions about patient care.
Consistency
Consistency in blood film reporting is essential for accurate diagnosis and treatment. Reports should maintain a uniform standard, regardless of whether the same individual or different colleagues produce them. This is particularly important when describing cells such as blast cells and atypical lymphocytes, which can vary significantly in appearance.
Standard Operating Procedures (SOPs)
Implementing SOPs provides a structured framework for analysing and reporting blood films. SOPs define the criteria for identifying and describing various cell types, ensuring all laboratory personnel adhere to the same standards. For example, SOPs might specify the morphological characteristics of blast cells, such as size, nuclear-to-cytoplasmic ratio, chromatin pattern, and features of atypical lymphocytes, such as irregular nuclear shape and basophilic cytoplasm. Regular review and updates of SOPs are necessary to incorporate the latest advancements in haematology and address any inconsistencies observed during quality assessments.
Training
Comprehensive training programs are essential for standardising blood film reporting. These programs should cover the identification and description of different cell types. Practical sessions, slide reviews, and proficiency testing help reinforce theoretical knowledge and improve diagnostic skills.
Quality Assessments
Quality assessments are vital for maintaining the reliability of blood film reports and can be categorised into internal and external assessments.
Internal Quality Assessments (IQA) are conducted within the laboratory to monitor and improve internal processes. Routine monitoring includes regular checks of equipment and procedures, such as microscope calibration and staining verification. Internal audits provide systematic reviews of laboratory processes to ensure compliance with protocols and identify areas for improvement. Proficiency testing, where known samples are analysed and results compared, validates the skills and accuracy of laboratory personnel. Peer reviews allow for collaborative examination of challenging cases, verifying findings and reducing errors.
External Quality Assessments (EQA) involve independent evaluations by external organisations to benchmark the laboratory against industry standards. Participation in proficiency testing programs, such as those provided by the National External Quality Assessment Service (NEQAS), includes analysing unknown samples and comparing the results with those of other laboratories. Inter-laboratory comparisons highlight variations and promote the adoption of best practices. External audits assess compliance with industry standards and provide feedback for improvement. The International Organization for Standardization (ISO) is the most common body overseeing these standards, including ISO 15189:2022, which specifies requirements for quality and competence in medical laboratories.
Understandability
Reports should be clear and understandable to the physicians and healthcare professionals who use them. Using correct terminology and providing detailed, specific descriptions of findings are crucial. For instance, instead of vague terms like “abnormal cells,” specifying “hypersegmented neutrophils” or “blast cells with Auer rods” provides clear and actionable information. A structured layout for reports ensures that important information is easily located and followed, with sections clearly labelled such as “Patient Information,” “Clinical History,” “Microscopic Findings,” and “Conclusion.”
Limitations
Recognising and addressing limitations that may hinder the accuracy of the report is essential. These limitations might include sample age, inadequate smearing, or lack of clinical information. It is crucial to reject samples that hinder accurate interpretation and request new samples if necessary.
Interpretation and Suggestions for Further Investigation
Analyse blood film findings in the context of the clinical information available. For example, a blood film request may be accompanied by the information “unwell patient.” If the blood film shows a leukemoid reaction with neutrophilia and left shift, interpret these as potential indicators of infection, G-CSF administration, or malignancy
Clearly explain findings. For instance, stating, “The blood film shows increased white cells”, is not helpful to the person caring for the patient. Instead, provide specific details such as, “The blood film shows increased neutrophils with left shift, suggesting a possible infection.”
Based on your findings, provide specific, actionable recommendations for further investigations to confirm the diagnosis. For example, if the patient shows signs of a possible infection, additional tests such as blood cultures or imaging studies should be recommended. Suggest follow-up actions, such as “Repeat full blood count and blood film analysis in 1-2 weeks” to monitor the patient’s condition and response to treatment.
Standardised Approach to Blood Film Reporting
Effective blood film reporting requires a methodical approach to ensure that no abnormalities are missed and that the information provided is accurate and helpful for patient care. Here are nine key steps to achieve this.
1. Verify Patient Details
Before examining the slide, ensure that the patient details on the slide match those in the laboratory information system. This verification step is crucial to ensure the report corresponds to the correct patient, especially when correlating it with a full blood count. Misidentifying patient samples can lead to incorrect diagnosis and treatment, making this initial verification step vital.
2. Macroscopic Examination
Examine the blood film macroscopically to assess its quality. Evaluate whether the film is adequate by looking for a proper monolayer and tail. Compare normal slides to those with abnormalities, which their distinctive appearances can identify. For instance:
- Normal Slide: Exhibits a gradient from the drop of blood to a thin monolayer, ending with a feathered tail
- Polycythemia: Appears darker and more densely packed with red cells.
- Anaemia: Looks paler due to the reduced number of red cells.
- Bluish Discoloration: Indicates the presence of markedly increased paraprotein or light chain levels, seen in multiple myeloma or high white cell counts from infections or leukaemias.
3. Slide Placement and Focus
Place the slide on the stage and ensure you are in a comfortable position to avoid strain. Adjust the microscope to the correct height to prevent neck or back discomfort. Ensure the slide is flat and properly clipped to prevent any movement.
4. Low-Power Examination
Begin with a low-power objective (typically 10x) to bring the specimen into focus and scan the entire slide. This initial scan helps identify large-scale abnormalities and prepares the slide for detailed examination. Cover a large area of the slide to identify critical abnormalities. Move systematically to avoid redundant examination of the same area. Low-power scanning helps in:
- Identifying Rare Cells: Nucleated red cells, blasts, and platelet clumps.
- Locating Key Areas: Finding the monolayer where cells are well-spread and not overlapping.
- Preliminary Assessment: Gaining an overall impression of the blood film’s cellularity and distribution.
5. High-Power Examination
Switch to higher power objectives (20x, 40x, and eventually oil immersion lenses 50x, 100x) to examine fine details. Ensure there is no oil residue on non-oil immersion lenses, as it can blur the images. Detailed examination involves:
- Identifying Fine Details: Such as intracellular inclusions and subtle morphological changes. Examples include basophilic stippling, malarial parasites, and Auer rods.
- Confirming Initial Findings: Verifying observations made under low power.
6. Standardised Descriptions
Use consistent and standardised terminology to describe abnormalities.
For instance, in iron deficiency anaemia, microcytosis and hypochromia are described based on established definitions.
- Microcytosis: Red cells are smaller than the nucleus of a small lymphocyte.
- Hypochromia: Central pallor of red cells extending to more than one-third of the cell’s diameter.
Use a grading system to quantify the severity of abnormalities. Options include describing if a feature is absent or present, using a numerical scale, using descriptive terms (mild, moderate, severe), or using percentage-based descriptions. For example:
- Normal: <5% of cells affected.
- Mild: 5-25%
- Moderate: 25-50%
- Marked (+3): More than 50% of cells are affected
Grading helps standardise reports and convey the extent of abnormalities accurately. The International Council for Standardization in Haematology (ICSH) recommendation on severity grading1 provides a useful guide. The ICSH uses a three-tiered grading system to classify the severity of findings based on the percentage of specific abnormalities observed in red cells, white cells, and platelets:
- 1+ Designation: Reserved exclusively for schistocytes, indicating ‘few’ or ‘rare.’
- 2+ Designation: Describes the abnormality of moderate severity in the observed cells.
- 3+ Designation: Used for ‘many’ cells, reflecting a significant presence of the observed abnormality.
Even small numbers of schistocytes are clinically significant, suggesting a diagnosis of a microangiopathic haemolytic anaemia like thrombotic thrombocytopenic purpura (TTP), a potentially fatal condition. However, this must represent a dominant feature, have supporting morphological features (e.g., polychromasia, thrombocytopenia), and be interpreted within the clinical context.
7. Handling Ambiguous Cells
Due to the subjective nature of blood film examination, encountering cells of ambiguous lineage is inevitable. While difficult to completely avoid, such ambiguity can be minimised through increasing experience and knowledge of normal cells. If you have limited blood morphology experience, studying normal blood films to build a solid foundation is beneficial
Interpreting findings in the context of other cells and overall abnormalities is crucial. For example, smear or smudge cells alone do not point towards a specific diagnosis. However, when these cells are observed in conjunction with mature lymphocytosis, especially if chronic, it suggests a diagnosis of a low-grade lymphoproliferative neoplasm, such as chronic lymphocytic leukaemia (CLL).
A-mature lymphocyte, B-smear (smudge) cell
8. Correlate with Clinical Details
Integrate clinical information with your morphological findings.
- Review the Patient’s Automated Blood Count: Ensure the blood film findings align with automated counts.
- Clinical History: Consider the patient’s clinical history, medications, symptoms, and clinical examination findings.
- Supplementary Investigations: Review related supplementary tests like radiological investigations and other laboratory tests.
For example, if a patient has microcytic hypochromic anaemia, the most likely diagnosis is iron deficiency anaemia, which can be confirmed by low serum ferritin.
9. Structured Report Writing
Use correct terminology and maintain a structured format to ensure your blood film report is clear and understandable. Begin with the patient information, including the patient’s name, date of birth, unique identifier, and the date of the report. Follow this with clinical details, outlining the reason for the request and any relevant medical history.
In the morphological findings section, provide a detailed description of red cells, white cells, and platelets. Include a miscellaneous section for other pertinent details, such as the presence of blast cells and microorganisms.
The conclusion should summarise the findings and suggest the next steps while noting any limitations to the report. If a manual differentiation count was performed, be sure to include it. For critical features, promptly inform the clinical team and ensure the slide is referred for senior review if necessary. This structured approach helps maintain clarity and comprehensiveness, ensuring the report is useful for clinical decision-making.
