Blood Tests

Normal Ranges

	Birth	1 yr	2-6 yrs	6-12 yrs	12-18 yrs
Haemoglobin g/dl	14-21	11-14	11.5-13.5	11.5-15.5	12-16
White Cells x10⁹/L	10-26	6-17.5	5-17	4.5-14.5	4.5-13
Platelets x10⁹/L	150-450 all ages
ErythrocyteSedimentationRate (ESR) mm/hr	<10
CReactiveProtein (CRP) mg/L	<10
Alanine aminotransferase ALT U/L	<40
Aspartate aminotransferase (AST) U/L	<50
Alkaline phosphatase (ALP) U/L	150-700	250-1000	250-850	250-950 GIRLS 250-730 BOYS	170-460 GIRLS 170-970 BOYS
Creatine kinase U/L	60 -300
Ferritin microgram/L	15-150 all ages

The full blood count reflects a systemic inflammatory process. Inflammatory markers measure disease activity to monitor progress and response to treatment. The C-reactive protein (CRP), Erythrocyte Sedimentation Rate (ESR) and Serum Ferritin are often very high with inflammation.
Creatine Kinase (CK) is an enzyme which leaks out of damaged muscles. It is elevated in muscular dystrophy or inflammatory muscle diseases. The rise in CK can be 10 - 100x normal.
Liver enzymes (AST and ALT) reflect liver function. They can be raised for a number of reasons - infection, drugs or disease. It is noteworthy that these enzymes are not only produced by the liver but also by muscle (in response to damage). Elevated liver enzymes in the presence of muscular dystrophy does therefore not reflect liver damage but muscle damage.
Autoantibodies are produced as a result of an immune process. They do not always represent disease. Antinuclear Antibodies (ANA) can be found in up to 15% of healthy children and can occur with viral infection and other non-rheumatic conditions. A persistently positive ANA can be associated with a number of rheumatological conditions including JSLE, drug-induced lupus, undifferentiated connective tissue disease, Sjögrens Syndrome, Juvenile Dermatomyositis, Scleroderma and Systemic Sclerosis. A positive ANA can occur in some children with JIA and associates with risk for chronic anterior uveitis.