Clinical Decision Support System

How to Read Lab Test Results to Diagnose Disorders
Interpreting lab results correctly is crucial for accurate diagnosis.
Here’s a step-by-step guide, along with insights on whether AI-driven tools like DDxHub can help.

Step 1: Understand the Basics of Lab Reports
Every lab report includes:

Test Name (e.g., Hemoglobin, TSH, Creatinine)

Your Result (e.g., 12.5 g/dL)

Reference Range (e.g., 13.0-17.0 g/dL)

Flag (High/Low/Normal)

Key Questions to Ask:
Is the result abnormal?

Compare your value to the lab’s reference range.

Example: If fasting glucose is 110 mg/dL (normal: 70-99), it suggests prediabetes.

How far is it from the normal range?

Slightly high/low may not be concerning, but severely abnormal values need attention.

Example:

Potassium: 5.6 mEq/L (normal: 3.5-5.0) → Mild hyperkalemia (may need retesting).

Potassium: 6.5 mEq/L → Medical emergency (risk of heart arrhythmia).

Is this a single abnormal result or a trend?

A one-time high value may be due to lab error or temporary factors (e.g., dehydration).

Consistent abnormalities (e.g., rising creatinine over months) indicate a real disorder.

Step 2: Link Lab Results to Symptoms
Example 1:

Symptoms: Fatigue, weight gain, dry skin

Lab: TSH = 8.5 mIU/L (high) → Hypothyroidism

Example 2:

Symptoms: Excessive thirst, frequent urination

Lab: Glucose = 220 mg/dL → Diabetes

Step 3: Use Differential Diagnosis (DDx) Approach
Differential diagnosis means listing possible causes of abnormal lab results.

Example:

Low Hemoglobin (Anemia)

Possible causes: Iron deficiency, B12 deficiency, chronic disease, bleeding.

Next steps: Check ferritin, MCV, B12 levels to narrow down.

Step 4: Confirm with Additional Tests
Single lab tests are rarely diagnostic-follow-up tests are often needed.

Example:

High Calcium → Check PTH, Vitamin D to rule out hyperparathyroidism.

High Liver Enzymes (ALT/AST) → Test for hepatitis, fatty liver, alcohol use.