Should Laboratory Test Results Be Included in Salient Features?
Yes, laboratory test results should absolutely be included in the salient features of a clinical case, as they provide objective evidence that is essential for diagnosis, risk stratification, and clinical decision-making.
Why Laboratory Results Are Essential Components
Laboratory data serve as objective evidence that complements clinical findings and are explicitly required by multiple clinical guidelines for establishing diagnoses. For heart failure diagnosis, guidelines mandate that objective evidence must consist of "at least 2 physical examination findings OR 1 physical examination finding and at least 1 laboratory criterion" 1. This demonstrates that laboratory results are not supplementary—they are foundational diagnostic criteria.
What Laboratory Results to Include
When presenting salient features, include laboratory results that:
Establish or support the diagnosis: For bleeding disorders, initial hemostasis tests (CBC, PT, PTT) are grade C recommendations that "can suggest whether coagulation factor deficiency or thrombocytopenia might be the potential cause of clinical bleeding" 2
Guide immediate management: In stroke evaluation, "initial bloodwork: hematology (complete blood count), electrolytes, coagulation (aPTT, INR), renal function (creatinine, e-glomerular filtration rate), random glucose or hemoglobin A1c, and troponin" should be routinely considered 3
Provide prognostic information: For heart failure, "increased BNP or NT-proBNP concentrations" with specific thresholds (BNP >500 pg/mL or NT-proBNP >2000 pg/mL in acute decompensated HF) are critical laboratory evidence 1
Differentiate between diagnoses: In cirrhosis with suspected DIC, declining fibrinogen levels and factor VIII/VWF levels help distinguish adaptive coagulation from consumptive coagulopathy 4
Critical Context Requirements
Laboratory results must always be interpreted within clinical context 5, 6, 7. Isolated laboratory values should never drive diagnosis independently—the entire clinical picture matters 7. A normal lactate doesn't exclude mesenteric ischemia, and a normal white blood cell count doesn't exclude acute cholecystitis 7.
Common Pitfalls to Avoid
Don't include irrelevant results: Only pertinent positive and negative findings belong in case presentations 8. Excessive detail obscures the essence of the report.
Don't report without timing: Laboratory evidence should specify when obtained relative to presentation (e.g., "within 24 hours of presentation" for heart failure) 1
Don't ignore pre-treatment values: Glucocorticoid treatment can affect laboratory results, particularly in conditions like giant cell arteritis 9. Document whether results were obtained before or after treatment initiation.
Don't forget reference ranges: Results should be compared to appropriate, biologically-based reference intervals that reflect the patient's demographic characteristics 10
Practical Algorithm for Inclusion
Start with tests that establish the diagnosis: Disease-specific biomarkers (troponin for MI, BNP for HF, D-dimer for PE)
Add tests that assess severity: Platelet count, coagulation studies, renal function
Include tests that guide treatment: INR for anticoagulation, drug levels, culture results
Document abnormal results with clinical significance: Not every mildly abnormal value needs emphasis—focus on those that change management 11
The Bottom Line
Laboratory results are not optional additions to clinical case presentations—they are required objective evidence that, when properly selected and contextualized, transform subjective clinical impressions into actionable diagnoses. The key is selecting only pertinent results and interpreting them within the full clinical context, avoiding both the extremes of omission and excessive detail.