10 important blood tests – normal values
In this article we will go through 10 important blood tests, and their normal values.
Most have more than one component.
There will be small local variations, as labs using different testing kits.
1. Full blood count (FBC)
- Haemoglobin (Hb) = 130-170 g/L (men); 110-150 g/L (women). Anaemia in when Hb is <130 in a man and <110 in a woman
- Mean cell volume (MCV) = 80-95 fL. If anaemic, MCV <80 = microcytic type (small red cells), >95 = macrocytic (large red cells)
- White cell count (WCC, or WC) = 4-11 x109/l. Rises in infection
- Platelets (Plts) = 150-400 x109/l. Low is thrombocytopenia; high is thrombocythaemia
2. C-reactive protein (CRP) <5 mg/L
Non-specific test rises in infection, inflammation and malignancy
3. Urea and electrolytes (U&Es), including kidney function, GFR and CKD stage
- Sodium (Na) = 135-145 mmol/L. A sodium <125 or >150 requires treatment today
- Potassium (K) = 3.5-5.3 mmol/L. A potassium <3.0 or >6.0 requires treatment today
- Chloride (Cl) = 95-105 mmol/L
- Bicarbonate (Bic) = 22-28 mmol/L (venous). Low in acidosis, high in alkalosis
- Urea (U) = 3-7 mmol/L. High in CKD or AKI. If >50, you need a reason not to dialyse
- Creatinine (Creat) = 60-120 μmol/L. High in CKD or AKI. If >500, you need a reason not to dialyse
- eGFR = 90-120 ml/min/1.73m². Low in CKD. This enables your CKD stage to be calculated
4. Liver enzymes (previously called liver function tests, or LFTs)
- Bilirubin (bili) = <21 µmol/l. High in liver disease
- Alkaline phosphatase (ALP) = 30-130 IU/l
- 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
5. Cholesterol tests
- Total cholesterol (chol) = 3-5 mmol/L
- HDL (‘good’) cholesterol. Target level = >1 mmol/L
- LDL (‘bad’) cholesterol. Target level = <4 mmol/L
- Triglyceride (TG). Target level = <1.7 mmol/L
- Cholesterol/HDL ratio = <4
6. Glucose and diabetes tests
Glucose
- Blood glucose = 4-6 mmol/L
- Prediabetes = 7-10 mmol/L. Needs to be monitored
- Diabetes = 11 mmol/L or more (or fasting >7 mmol/L). May need treatment
HbA1C (reflects diabetic control over previous 3 months)
- HbA1c = 20-42 mmol/mol (or 4-6%)
- Prediabetes = 42-47 mmol/L (6-6.5%). Needs to be monitored
- Diabetes = 48 mmol/mol or over (>6.5%). May need treatment
7. Thyroid-stimulating hormone (TSH) = 0.4-5.0 mU/L
High with an underactive thyroid, low with overactive.
8. Bone biochemistry
- Calcium (Ca) = 2.2-2.6 mmol/L. Below 1.6 or above 3.0 needs treatment
- Magnesium (Mg) = 0.7–1.0 mmol/L
- Phosphate (PO4)= 0.8-1.4 mmol/L
- Parathyroid hormone (PTH) <5 pcmol/L
- Vitamin D = >50 nmol/L
9. 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
10. Prostate specific antigen (PSA; men only) = <3 ng/ml
Can be raised in Ca prostate
Other blood tests
Arterial blood gases (these are 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.
Summary
We have been through 10 important blood tests, and given their normal values. We hope it has been helpful.
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