Blood Results

 

Normal haematology values

Male Female

Hb (g dl) 13 18 11.5 15.5

PCV (haematocrit) 0.42 0.53 0.36 0.45

RCC (x 1012/l) 4.5 6 3.9 5.1 (about 5 million mm3)

MCV (fl) 80 96 (10-15)

MCH (pg) 27 33 (10-12)

MCHC (g/dl) 32 35

WCC (109/litre) 4 11 (about 7 000 mm3)

Neutrophils (109/litre) 3.5 - 7.5

Eosinophils (109/litre) 0.04 - 0.4

Basophils (109/litre) 0.01 - 0.1

Lymphocytes (109/litre) 1.5 - 4

Monocytes (109/litre) 0.2 - 0.8

Platelets (109/litre) 150 - 400

ESR (mm/hour) <15 <20

Reticulocytes (%) 0.5 2.5

 

Haemoglobin

The mass of haemoglobin for a given volume of blood

 

Causes of low

Anaemia Hypervolaemia Haemorrhage

 

Causes of high

Dehydration Polycythaemia COPD

 

Alterations in Hb may be genuine or spurious

 

 

Packed cell volume

 

The percentage of blood volume which is cells, also called haematocrit

 

Causes of low

Haemorrhage Anaemia

 

Causes of high

Increased red cell production Polycythaemia Chronic hypoxia Dehydration Adaptation to altitude

 

Red cell count

The number of erythrocytes in a given volume of whole blood

 

Causes of low

Haemorrhage Fluid overload

 

Causes of high

Polycythaemia Dehydration

 

Mean corpuscular volume of red cells

 

An evaluation of the average volume of each red cell derived from the ratio of the haematocrit to the total number of red cells

 

Causes of low

Microcytic anaemias eg. Iron deficiency, thalassaemia, anaemia of chronic disease, sideroblastic anaemia,

Chronic blood loss

 

Causes of high

Macrocytic anaemias, eg. Vit B12 of folic acid deficiency

In normocytic anaemias the MCV will be normal eg. In liver disease, alcohol abuse and haemolytic

Myxoedema Alcohol or liver disease

 

 

Mean corpuscular haemoglobin

The amount of haemoglobin in an average erythrocyte, derived from the ration between the amount of haemoglobin and the number of red cells present

 

Causes of low

Hypochromic anaemia eg. iron deficiency Thalassaemia

Chronic blood loss Megaloblastic anaemia

 

Causes of high

B12 or foliate deficiency Myxoedema

 

 

Mean corpuscular haemoglobin concentration

 

An estimation of the concentration of haemoglobin per 100 mls of packed cells, derived from the ratio between the haemoglobin and the haematocrit

 

Causes of low

Iron deficiency Blood loss Thalassaemia

 

Causes of high

Spherocytosis Sickle cell disease

 

HbA1c

The proportion of haemoglobin which is glycosolated

 

 

White cell count

Total number of circulating leucocytes

 

Causes of low (leucopenia)

Viral infections

Bone marrow failure, megaloblastic anaemia, hypersplenism, overwhelming sepsis, autoimmunity, drug induced

 

Causes of high (leucocytosis)

Infections, trauma, infarcts, chronic inflammatory disease, malignant neoplasms, steroid therapy, leukaemias, renal failure, diabetes mellitus

 

Differential White cell counts

 

Neutrophils

 

Causes of Neutrophilia

Response to acute infection Stress, adrenaline and steroids Tissue damage

 

Causes of neutropenia (agranulocytosis)

Some viral infections

TB, RA, SLE

Aplastic anaemia, may be secondary to cytotoxic drugs or starvation

Drug ADRs, type 1 or type 2

 

Counts less than 1 predispose to infections, less than 0.5 predisposes to life threatening infections

 

Lymphocytes

 

Causes of lymphocytosis

Viral infections Hepatitis Infectious mononucleosis

Infectious hepatitis Measles, mumps TB, EBV

Toxoplasmosis Chronic infections May be associated with enlarged lymph nodes

 

Monocytes

 

Causes of monocytosis

Infectious mononucleosis Hodgkin`s disease Recuperative phase of infections

TB and other chronic bacterial infections

 

Eosinophils

 

Causes of eosinophilia

Allergic reactions Asthma Parasitic infections Some cancers

 

Basophils

 

Causes of basocytosis

Hypothyroidism Ulcerative colitis

 

Erythrocyte sedimentation rate

 

The rate of fall of the red cells in a column of blood

A measure of the acute phase response.

C - reactive protein is an acute phase protein, produced in the liver and rises within 6 hours of an acute event, it also rises with pyrexia

The pathological process may be immune, infective, ischaemic, malignant or traumatic

ESR increases with age, higher in females

 

Causes of low

Polycythaemia vera

 

Causes of high

Increase in plasma fibrinogen or immunoglobulins

Increased serum proteins cause rouleax formation, therefore increase sedimentation

Severe anaemia

Plasma viscosity is sometimes used instead of ESR

 

Reticulocytes

Contain residual ribosomal RNA and mature within 1 - 2 days of release into the circulation

 

A guide to erythroid activity in the bone marrow

 

Causes of low

In the presence of anaemia may indicate an inappropriate response by the bone marrow or deficiency of a haematinic

 

Causes of high

Haemorrhage, haemolysis, response to treatment with a haematinic

 

 

Platelets

A count below 20 (ie. 20 x 109/litre) causes spontaneous bleeding

 

Causes of low (thrombocytopenia)

Failure of platelet production; eg. Leukaemia, marrow infiltrations, hypoplastic anaemia, chemotherapy, alcohol, viral infections

 

Increased destruction of platelets; eg. Autoimmune Thrombocytopenic purpura, drug induced, DIC, post - transfusional, neonatal, splenomegaly

 

Chemotherapy

 

Causes of high (thrombocytosis)

Acute or chronic blood loss, Iron deficiency, chronic inflammatory disease, (eg. RA), malignant disease

 

In some cases bleeding time may be increased

 

Coagulation studies

 

Bleeding time

2.5 - 9 minutes

 

Increased in

Aspirin ingestion Thrombocytopathology Uremia Anticoagulation therapy

 

Prothrombin time (PT)

Often used with INR in warfarin therapy 11 - 16 seconds

Time taken for blood to clot from the prothrombin stage

 

 

Partial thromboplastin time (PTT)

Often used in heparin therapy

 

INR

International ratio of patients prothrombin time compared to an agreed control

 

Used to monitor anticoagulation treatments

 

Therapeutic range depends on the condition eg. DVT range = 2 - 3, Artificial heart valves and repeated thromboembolism = 3 - 4.5

 

Causes of high

Blood slow to clot Deficiency of prothrombin DIC Vit K deficiency

 

Causes of low

Blood clots too quickly

 

 

D - Dimer test

Measures breakdown products of plasma fibrin clots

Elevated in DIC, DVT, PE, after thrombolytic therapy, surgery or trauma

 

Biochemistry

 

Liver function tests

 

Serum bilirubin

Normal range for total bilirubin 2 - 22 umol/L Clinical jaundice > 35

Normal range for Conjugated bilirubin 0 - 10 umol/L

Also check for urinary bilirubin and urobilinogen

 

Raised bilirubin suggests

Hepatitis Biliary stasis Increased haemolysis

 

Alkaline phosphatase

An indicator of liver and bone disease, may also come from gut and placenta, normal range 40 - 117 U/L

Levels in children are 2 - 3 times higher than in adults

Levels are raised post fracture

The liver excreted Alk Phos into the bile so if there is obstructive biliary disease the serum levels are raised

 

Aspartate aminotransferase

Normal adult range 12 - 44 U/L

Found in high concentrations in heart, liver, RBCs, skeletal muscle

Formally known as SGOT

Raised in hepatocellular liver disease such as viral hepatitis, moderately raised in hepatic obstruction

 

Gamma glutamyl transpeptidase (Gama GT)

Normal range, male = 18 - 70 U/L, female = 12 - 42 U/L

 

May be raised by liver cell damage, excessive alcohol intake, MI, CVA, diabetes and chronic lung disease

 

 

Serum amylase

Normal range 30 - 90 U/L

 

May be raised in bile duct obstruction, perforated duodenal ulcer, small bowel obstruction, renal failure and ectopic pregnancy

 

      1200 = acute pancreatitis

 

 

Glucose

Normal range 3.5 - 8.5 mmol/L

 

Lipids

Cholesterol and triglycerides are transported through the blood by lipoproteins

 

50% of cholesterol is synthesised by the liver

 

Total cholesterol desirable < 6.5 for women and < 6.0 for men. Less the 5.2 desirable in ischaemic heart disease

 

HDL normally 0.9 - 1.6

LDL 3.35 - 4, abnormal if >5

HDL should be > 0.2 of total cholesterol

 

Cardiac enzymes

Creatine kinase normal male = 58 - 205, female 20 - 192 U/L

AST normal = 13 - 44 U/L

Lactate dehydrogenase, normal =285 - 577 U/L

Isoenzymes

Troponins T and I released after 2 4 hours and persist for up to 7 days

 

Ca++/ Proteins

Calcium and proteins are measured together because calcium is protein bound to some extent in the plasma.

 

Causes of hypoproteinaemia

 

 

Immunology and virology

Viral studies look for the presence of antigen in a sample

 

Antibody titres assess the levels of antibodies in the plasma

 

Bacteriology

Blood cultures detect and identify the form of bacteria in the blood