How do you analyze and interpret the results of a haematology report?

Haematology Report Analysis and Interpretation

Analyze haematology reports systematically by first reviewing the complete blood count (CBC) parameters—including white blood cell (WBC) count, red blood cell (RBC) count, hemoglobin, hematocrit, platelet count, and cell indices—then examining the peripheral blood smear for morphological abnormalities, followed by correlation with clinical context and consideration of potential spurious results before determining if specialized testing is warranted. 1, 2

Initial Assessment: Core Parameters

Complete Blood Count Components

• WBC count and differential: Evaluate total WBC count and automated differential percentages for neutrophils, lymphocytes, monocytes, eosinophils, and basophils 3, 1
• RBC parameters: Assess RBC count, hemoglobin concentration, hematocrit, mean cell volume (MCV), mean cell hemoglobin (MCH), and mean cell hemoglobin concentration (MCHC) 4, 5
• Platelet count: Review platelet number and mean platelet volume (MPV) 4
• Reticulocyte count: When available, assess reticulocyte percentage and absolute count to evaluate bone marrow response 4, 5

Critical Index: MCHC

MCHC is the most important calculated RBC index for detecting spurious results and should be evaluated before accepting other parameters as valid 4, 5. MCHC values outside the normal range (typically 32-36 g/dL) often indicate measurement errors or interfering substances.

Recognition of Spurious Results

Common Causes of False WBC Counts

• Spuriously low WBC: EDTA-induced agglutination can falsely decrease WBC counts 4
• Spuriously high WBC: Nucleated RBCs, insufficiently lysed RBCs, platelet aggregates, cryoglobulins, or severe hyperlipidemia can falsely elevate WBC counts 4, 5

Common Causes of False RBC/Hemoglobin Values

• Spuriously high hemoglobin: Severe hyperlipidemia, elevated WBC counts (>50,000/μL), or cryoglobulins interfere with hemoglobin measurement 4, 5
• Spuriously high MCV: Cold agglutinins, hyperglycemia (>600 mg/dL), marked hypernatremia, or excess anticoagulant can falsely elevate MCV 4, 5

Analyzer Flags and Scattergrams

• Review all instrument flags: Modern analyzers generate flags indicating potential abnormalities or interferences that require manual review 4, 6
• Examine WBC differential scattergrams: Abnormal scattergram patterns alert to the presence of atypical cells, blasts, or interfering substances 4
• Note: Sophisticated analyzers with differential scattergrams have superior sensitivity for detecting spurious results compared to simpler instruments 4, 5

Peripheral Blood Smear Examination

When Manual Review is Required

Manual microscopy is mandatory when the analyzer flags abnormalities and remains the reference method for WBC differential counts 6. Automated microscopy analyzers can provide accurate differentials but should not replace cytologist review for complex cases 6.

Key Morphological Features to Assess

• RBC morphology: Size variation (anisocytosis), shape abnormalities (poikilocytosis), color changes (hypochromia, polychromasia), inclusions (basophilic stippling, Howell-Jolly bodies) 7
• WBC morphology: Nuclear and cytoplasmic maturation, presence of blasts or atypical cells, toxic granulation, Döhle bodies 6
• Platelet morphology: Size variation, clumping, presence of giant platelets 6

Clinical Context Integration

Correlation with Clinical Presentation

• Bleeding history: For patients with bleeding symptoms, assess activated partial thromboplastin time (APTT), prothrombin time (PT), fibrinogen levels, and von Willebrand factor (VWF) antigen and function as first-line tests 1, 2
• Family history: Document family history of bleeding or hematologic disorders, as 98% of specialists consider this essential 1
• Medication history: Record all medications including over-the-counter NSAIDs, as 88% of specialists document this routinely 1

Iron Status Assessment

Iron studies (serum iron, ferritin) should be included in the initial evaluation, as iron deficiency is commonly overlooked despite being frequent in patients with bleeding disorders 1. This is performed by 69% of specialists as first-line testing 1.

Specialized Testing Indications

For Bleeding Disorders with Normal Initial Tests

When standard coagulation studies are normal but bleeding symptoms persist:

• Factor assays: Test factors VIII, IX, and XI (performed by 62% of specialists first-line), then factors II, V, VII, X, and XIII if initial testing is unrevealing 1, 2
• Platelet function testing: Light transmission aggregometry with multiple agonists (ADP, collagen, epinephrine, ristocetin, arachidonic acid) is recommended by 60% of specialists as second-line testing 1, 2
• VWF multimer analysis: Perform when VWF:RCo is abnormally low or the ratio of VWF:RCo to VWF:Ag is below 0.5-0.7 3, 2

For Suspected Hematologic Malignancies

• Cytogenetic analysis: For suspected leukemia or lymphoma, chromosome banding analysis and FISH should be performed using the most recent ISCN nomenclature 3
• Flow cytometry: Provides rapid differential diagnosis of acute leukemias based on peroxidase content and cell volume discrimination 8
• Reporting timeline: Urgent referrals (acute leukemia) should have 95% reported within 10 calendar days, with rapid FISH/PCR results in <24 hours 3

Reporting Standards for Specialized Tests

Essential Report Components

• Two unique patient identifiers (date of birth, full name) 3
• Sample information: Type, source, date of referral, date of report, unique sample identification 3
• Analytical details: Number of cells analyzed, probe manufacturers for FISH, genome build for array results 3
• Gene nomenclature: Use HUGO gene nomenclature with fusion products written as BCR-ABL1 (using "-" not "/") 3
• Clinical interpretation: Relationship of abnormalities to referral reason, disease classification using WHO 2017 nomenclature, and prognosis based on robust data from large trials 3

Critical Reporting Pitfalls to Avoid

• Never use "positive/negative" terminology for FISH results; instead state "abnormal" or describe specifically (e.g., "KMT2A rearrangement is present in XX cells") 3
• Avoid long reports that detract from clarity; methodology and limitations should not take prominence 3
• Do not report single-cell anomalies in the ISCN karyotype, though they may be mentioned in the written description with qualifications 3

Algorithmic Approach for Specific Scenarios

For Suspected Von Willebrand Disease

1. Initial screening: VWF:RCo, VWF:Ag, and Factor VIII levels 3
2. Calculate ratio: If VWF:RCo/VWF:Ag ratio is <0.5-0.7, proceed to specialized testing 3
3. Multimer analysis: Only perform if initial tests are abnormal or clinical suspicion is high 3
4. Avoid routine use of bleeding time or PFA-100 as screening tests due to conflicting sensitivity/specificity data 3

For Bleeding Disorder of Unknown Cause (BDUC)

When comprehensive testing is normal but bleeding symptoms persist (representing up to 60-70% of mild-moderate bleeding phenotypes):

• Use Bleeding Assessment Tool (BAT): 80% of specialists use BAT, with ISTH BAT being most common (73%) 1
• Consider second-line testing: Factor XIII (60% of specialists), platelet function testing (60%), fibrinolysis assays (38%), or genetic testing (48%) 1
• Management approach: Tranexamic acid is favored for prophylaxis for minor/major surgeries and during pregnancy 1, 2

For Immune Thrombocytopenia (ITP) Diagnosis

Basic evaluation includes:

• Patient and family history, physical examination, complete blood count with reticulocyte count, peripheral blood smear 3
• Direct antiglobulin test, quantitative immunoglobulin levels (especially in children with persistent/chronic ITP) 3
• HIV testing recommended for all adults regardless of geographic location 3
• Bone marrow examination only in selected patients when diagnosis is uncertain 3