Lab Interpretation Guide
How to Interpret Blood Test Results
CBC · Metabolic Panel · Liver · Kidney · Thyroid · Complete Guide
Key Principle
A single abnormal value rarely tells the full story. Blood test interpretation requires correlating multiple values, clinical context, patient demographics, and symptoms together — patterns matter more than individual numbers.
Complete Blood Count (CBC)
Marker
↓ Low
↑ High
Hemoglobin
Anemia — iron, B12, folate deficiency, bleeding, chronic disease
Polycythemia, dehydration, lung disease
Hemoglobin
↓ Anemia — iron, B12, folate deficiency, bleeding, chronic disease
↑ Polycythemia, dehydration, lung disease
WBC
Bone marrow suppression, viral infection, medications
Bacterial infection, inflammation, leukemia, stress response
WBC
↓ Bone marrow suppression, viral infection, medications
↑ Bacterial infection, inflammation, leukemia, stress response
Platelets
Bleeding risk, ITP, bone marrow disease, DIC
Reactive thrombocytosis, iron deficiency, infection
Platelets
↓ Bleeding risk, ITP, bone marrow disease, DIC
↑ Reactive thrombocytosis, iron deficiency, infection
MCV
Microcytic anemia — iron deficiency, thalassemia
Macrocytic anemia — B12/folate deficiency, liver disease
MCV
↓ Microcytic anemia — iron deficiency, thalassemia
↑ Macrocytic anemia — B12/folate deficiency, liver disease
Metabolic Panel
Marker
↓ Low
↑ High
Glucose
Hypoglycemia — insulin excess, fasting, Addison's
> 7.0 mmol/L fasting = diabetes mellitus
Glucose
↓ Hypoglycemia — insulin excess, fasting, Addison's
↑ > 7.0 mmol/L fasting = diabetes mellitus
Creatinine
Muscle wasting, low protein intake, early pregnancy
Renal impairment — acute or chronic
Creatinine
↓ Muscle wasting, low protein intake, early pregnancy
↑ Renal impairment — acute or chronic
Sodium
< 135 mmol/L — SIADH, heart failure, medications
> 145 mmol/L — dehydration, diabetes insipidus
Sodium
↓ < 135 mmol/L — SIADH, heart failure, medications
↑ > 145 mmol/L — dehydration, diabetes insipidus
Potassium
< 3.5 mmol/L — diuretics, vomiting, diarrhea
> 5.0 mmol/L — renal failure, acidosis, medications
Potassium
↓ < 3.5 mmol/L — diuretics, vomiting, diarrhea
↑ > 5.0 mmol/L — renal failure, acidosis, medications
Liver Panel
Marker
↓ Low
↑ High
ALT / AST
Not clinically significant
> 2× ULN = hepatocellular damage — hepatitis, drugs, alcohol
ALT / AST
↓ Not clinically significant
↑ > 2× ULN = hepatocellular damage — hepatitis, drugs, alcohol
Bilirubin
Not significant
> 21 µmol/L — hemolysis, liver disease, bile duct obstruction
Bilirubin
↓ Not significant
↑ > 21 µmol/L — hemolysis, liver disease, bile duct obstruction
Albumin
< 35 g/L — malnutrition, liver failure, inflammation, nephrotic syndrome
Dehydration (rarely significant)
Albumin
↓ < 35 g/L — malnutrition, liver failure, inflammation, nephrotic syndrome
↑ Dehydration (rarely significant)
GGT
Not significant
> 2× ULN — alcohol, liver disease, enzyme induction by medications
GGT
↓ Not significant
↑ > 2× ULN — alcohol, liver disease, enzyme induction by medications
Common Interpretation Mistakes
- •Treating a single abnormal value as a diagnosis — patterns matter more than individual values
- •Ignoring sex and age variation — hemoglobin, creatinine, ALT have different normal ranges
- •Overlooking medication effects — statins affect CK, metformin affects B12, diuretics affect electrolytes
- •Not considering timing — fasting vs non-fasting changes glucose, triglycerides, iron
- •Missing trending — a value 'within range' that has doubled over 6 months may be clinically significant
Need structured interpretation of your blood test?
STRUCTA MED analyzes blood test results automatically — detecting patterns across CBC, metabolic panel, liver and kidney function, and generating a clinical summary with risk assessment.
Analyze Blood Test Free →