List of normal lab values – and what they mean

List of normal lab values – and what they mean

In this article, we will describe the normal lab values of 10 commonly measured blood tests.

1. Normal full blood count (FBC)

• Haemoglobin (‘Hb’)
  • 130-170 g/L for men
  • 110-150 g/L for women
  • The Hb reflects the number of red cells (which carry oxygen) in the blood – a higher number means more red cells. A low haemoglobin is called anaemia. A high haemoglobin is called polycythaemia
• White cell count (WC) = 4-11 x10^9/L (million per litre). These cells fight infection (and cancer and foreign bodies inside you)
• Platelet count = 150-400 x10^9/L (million per litre). These cells clot the blood.

2. Normal U+E

• Sodium (Na) = 135-145 mmol/L. A sodium <125 or >150 requires treatment today. Low or high can affect the function of the brain. If very low or high, the patient can become drowsy or even unconscious
• Potassium (K) = 3.5-5.3 mmol/L. A potassium <3.0 or >6.0 requires treatment today. Low or high can affect the function of the heart (and even stop)
• Chloride (Cl) = 95-105 mmol/L
• Bicarbonate (Bic) = 22-28 mmol/L (venous). Low indicates high acid/low alkali levels (acidosis); high indicates low acid/high alkali levels (alkalosis)
• Urea (U) = 3-7 mmol/L. High in CKD or AKI. If >50, you need a reason not to have dialysis
• Creatinine (Creat) = 60-120 μmol/L. High in CKD or AKI. If >500, you need a reason not to have dialysis
• Glomerular filtration rate (GFR) = 90-120 ml/min/1.73m². Low in CKD – how your CKD stage is calculated.

3. Normal glucose and HbA1c

• Blood glucose = 4-6 mmol/L – and less than 8 mmol/L, two hours after a meal
  • Prediabetes is diagnosed if your random blood glucose = 7-11 mmol/L
  • Diabetes is diagnosed if you have a random blood glucose > 11 mmol/L (or a fasting blood glucose > 7 mmol/L)
• Haemoglobin A1c (HbA1c) = 20-42 mmol/mol (or 4-6%)
  • Prediabetes is diagnosed if your HbA1c = 42-47 mmol/mol (6-6.5%)
  • Diabetes is diagnosed if your HbA1c > 47 mmol/mol or over (>6.5%).

4. Normal bone biochemistry

• Calcium (Ca) = 2.2-2.6 mmol/L – below 1.8 or above 3.0 needs treatment; below 1.4 or above 3.5 needs treatment today. It is the primary mineral in bones, and is crucial for bone health. About 99% of your body’s calcium is in your bones and teeth. The other 1% of it is in your blood
• Phosphate (PO4) = 0.8-1.4 mmol/L – also essential for bone structure and works in conjunction with calcium
• Alkaline phosphatase (alk phos, ALP) = 30-130 U/L – an enzyme that indicates bone formation activity, with elevated levels signifying increased bone turnover
• Magnesium (Mg) = 0.7–1.0 mmol/L – also essential for bone structure, and works in conjunction with calcium
• Parathyroid hormone (PTH) <5 pcmol/L – a hormone that is made by 4 parathyroid glands (at the back of the thyroid gland in the neck). It controls calcium and phosphate levels in the bones and blood
• Vitamin D (vit D) >50 nmol/L – works with PTH.

5. Normal liver function tests (LFTs) – also called liver enzymes

• Bilirubin (bili) = <21 µmol/L. High in liver disease
• Alkaline phosphatase (alk phos, ALP) = 30-130 IU/L. There are bone and liver subtypes of alk phos
• ɣ–glutamyl transpedtidase (GGT) = 1-55 IU/L
• Alanine aminotransferase (ALT) = 15-45 IU/L
• Aspartate aminotransferase (AST) = 15-42 IU/L
• Albumin (Alb) = 35-50 g/L. Low in liver disease
• Globulin (Glob) = 20-40 g/L
• Total protein (TP) = 60-80 g/L.

6. Normal cholesterol (and lipids)

• Total cholesterol (chol) = 3-5 mmol/L – overall amount of cholesterol in your blood
• HDL (‘good’) cholesterol. Target level = >1 mmol/L – may make you less likely to have a heart attack or stroke
• Non-HDL/LDL (‘bad’) cholesterol. Target level = <4 mmol/L – may make you less likely to have a heart attack or stroke
• Triglyceride (TG). Target level = <1.7 mmol/L
• Cholesterol/HDL ratio = <4.

7. Normal thyroid levels

• TSH: 0.5 – 5.0 mU/L. This is the most important thyroid test. High TSH indicates an underactive thyroid, low indicates overactive
• Free thyroxine (T4): 8.0 – 18.0 pmol/L
• Free triiodothyronine (T): 3.8 – 6.0 pmol/L.

8. Normal cardiac (heart) biomarkers

• B-type natriuretic peptide (BNP) = <100 pg/mL. Sign of heart failure
• Aminoterminal pro B-type natriuretic peptide (NT-proBNP) = <400 pg/mL. Another test for heart failure.

9. Normal PSA level

• Prostate specific antigen (PSA; men only) = <3 ng/ml. A high level of PSA can be a sign of prostate cancer. But your PSA level can also be raised in prostate conditions that are not cancer (see here).

10. Normal INR

• INR (international normalised ratio) = 0.8-1.1 – for people who don’t take blood thinners. It measures how long it takes for your blood to clot. It’s often used to monitor people taking blood thinners, such as warfarin.

Other tests

Normal CRP

Normal ABGs (arterial blood gases) – usually only done when in hospital, if unwell

• pH: 7.35-7.45. Below 7.35 is acidosis (too much acid in the blood), above 7.45 is alkalosis (too much alkali in the blood); <7.3 needs action today
• pO2 = 11-13 kPa. Below 10 is hypoxia (low oxygen level in blood)
• pCO2 = 4.5-6 kPa. Above 6 is hypercapnia (high carbon dioxide in blood)
• HCO3 = 22-26 mmol/L. Below 22 is acidosis, above 26 is alkalosis
• Base excess (BE) = -2 to +2 mmol/L
• Lactate = 0.5-2.0 mmol/L. >2 needs action today
• O2 saturation = 94-98%. Below 90% needs action today.

Normal urinary ACR (uACR)

• Normal’ uACR = <3 mg/mmol
• This number reflects the amount of protein in the urine – a higher number means more protein. For this test, a lower number is better
• An uACR level of 3 mg/mmol or higher is called ‘microalbuminuria’
• A raised uACR can be an early sign of chronic kidney disease (CKD) – and/or a sign you may get higher albuminuria levels later.

Summary

We have described the normal lab values of 10 commonly measured blood tests. We hope it has been helpful.