Blood tests are a routine part of healthcare, used to diagnose conditions, monitor treatment, and assess overall health. Understanding what your results mean can help you have informed conversations with your doctor. This guide explains the most common blood tests and their significance.
Full Blood Count (FBC / CBC)
The most commonly ordered blood test, it evaluates the components of your blood:
Haemoglobin (Hb)
- Carries oxygen in red blood cells
- Normal range: Men 130-170 g/L; Women 120-150 g/L
- Low: May indicate anaemia (iron deficiency, B12 deficiency, chronic disease)
- High: May indicate dehydration, lung disease, or polycythaemia
White Blood Cells (WBC)
- Part of the immune system
- Normal range: 4.0-11.0 x10^9/L
- High: May indicate infection, inflammation, or stress
- Low: May indicate viral infection, bone marrow problems, or medication effects
Platelets
- Help blood clot
- Normal range: 150-400 x10^9/L
- Low: Risk of bleeding; may indicate infection, medication effects, or bone marrow issues
- High: May indicate infection, inflammation, or iron deficiency
Metabolic Panel
Blood Glucose
- Fasting glucose: Normal below 5.5 mmol/L (100 mg/dL)
- Pre-diabetes: 5.6-6.9 mmol/L (100-125 mg/dL)
- Diabetes: 7.0 mmol/L or above (126 mg/dL) on two separate occasions
HbA1c (Glycated Haemoglobin)
- Reflects average blood sugar over the past 2-3 months
- Normal: Below 42 mmol/mol (6.0%)
- Pre-diabetes: 42-47 mmol/mol (6.0-6.4%)
- Diabetes: 48 mmol/mol or above (6.5%)
- For people with diabetes, the individual target is set by your doctor (often below 53 mmol/mol or 7%)
Kidney Function (U&E)
- Creatinine: Waste product filtered by the kidneys
- eGFR: Estimated glomerular filtration rate - the best estimate of kidney function. Normal is above 90 mL/min
- Urea: Another waste product
- Sodium and potassium: Essential electrolytes
Liver Function Tests (LFTs)
- ALT (alanine transaminase): Elevated in liver inflammation or damage
- AST (aspartate transaminase): Similar to ALT
- ALP (alkaline phosphatase): Elevated in bile duct problems, bone disease
- Bilirubin: Elevated in liver disease, bile duct obstruction, or increased red blood cell breakdown
- Albumin: Low in liver disease, kidney disease, or malnutrition
Lipid Profile (Cholesterol Test)
- Total cholesterol: Desirable below 5 mmol/L
- LDL ("bad") cholesterol: Below 3 mmol/L (lower targets for high-risk individuals)
- HDL ("good") cholesterol: Above 1.0 mmol/L (men), above 1.2 mmol/L (women)
- Triglycerides: Below 1.7 mmol/L
Fasting for 10-12 hours before a lipid profile gives the most accurate results, though non-fasting samples can still be useful.
Thyroid Function
- TSH (Thyroid-Stimulating Hormone): Normal approximately 0.4-4.0 mIU/L
- High TSH: may indicate underactive thyroid (hypothyroidism)
- Low TSH: may indicate overactive thyroid (hyperthyroidism)
- Free T4: The active thyroid hormone level
Inflammation Markers
- CRP (C-Reactive Protein): A general marker of inflammation. Elevated in infections, autoimmune conditions, and tissue injury
- ESR (Erythrocyte Sedimentation Rate): Another inflammation marker
Vitamin and Mineral Levels
- Vitamin D: Widely tested in the UAE due to high prevalence of deficiency. Normal is generally above 50 nmol/L (20 ng/mL)
- Vitamin B12: Important for nerve and blood cell health. Low levels cause anaemia and neurological symptoms
- Folate: Works with B12 in red blood cell production
- Iron studies: Ferritin (iron stores), serum iron, transferrin, transferrin saturation
Tips for Accurate Results
- Follow fasting instructions (typically 8-12 hours for glucose and lipid tests)
- Stay hydrated (plain water is fine during fasting)
- Tell your doctor about all medications and supplements (some affect results)
- Time of day matters: Some tests vary with time (e.g., cortisol is highest in the morning)
- Ask your doctor if you are unsure about any instructions
Understanding "Abnormal" Results
- A result outside the normal range does not always mean something is wrong
- Normal ranges cover 95% of the healthy population - some healthy people fall slightly outside
- Results should always be interpreted in the context of your symptoms, medical history, and other tests
- Mildly abnormal results may need repeating before further investigation
- Your doctor is the best person to interpret your results
This article is for informational purposes only and does not replace professional medical advice. Always discuss your blood test results with your doctor.