This website used cookies to give you the best experience. By continuing to use this website you are consenting to cookies being used. You can delete and block cookies from within your browsers settings. For more information please refer to our privacy and cookie policy page.

Continue

Blood and Urine tests

Laboratory tests help establish a diagnosis and are integral to monitoring disease activity, safety of immunosuppressive medications and are important as part of clinical trials.

A few important points to note with investigations  

  • Blood tests or urine tests or their results are not always needed for a referral. If there is clinical concern, do not delay making the referral.
  • Children with Juvenile Idiopathic Arthritis (JIA) can have normal blood tests.
  • Inflammatory markers (acute phase proteins) include C-reactive protein (CRP), Erythrocyte Sedimentation Rate (ESR) and Ferritin.
  • A sudden drop in ESR, or dramatic rise in serum ferritin with low or falling haemoglobin or platelet count suggests onset of macrophage activation syndrome.
  • Immunosuppressed children, particularly children using interleukin-1 or interleukin-6 blockade, may not mount a normal immune response to infection - the CRP may be misleadingly normal even in a child with sepsis.
  • Creatine Kinase (CK) is an enzyme which leaks out of damaged muscles and is elevated in muscular dystrophy or inflammatory muscle diseases.  In muscular dystrophies there is usually a rise in CK, often about 10-100x normal range.
  • Liver enzymes (AST [aspartate aminotransferase] and ALT [alanine aminotransferase]) are raised with liver inflammation (e.g. infection or medicines) but can also be raised in muscular dystrophy.
  • HLA B27 (human leukocyte antigen B27) is a genetic marker found in many healthy people. In the presence of inflammatory arthritis, HLA B27 associates with axial spine involvement and acute uveitis.
  • Rheumatoid Factor (RF) is not diagnostic for JIA;  less than 5% children with JIA are RF positive.
  • Antinuclear Antibodies (ANA) are found in up to 15% of healthy children and can occur with viral infection and other non-rheumatic conditions. A persistently positive ANA can associate with a rheumatological conditions including JSLE. A positive ANA occurs in some children with JIA and carry higher risk for chronic anterior uveitis.
  • Abnormal urinalysis occurs for many reasons such as renal disease in JSLE or infection.

Why register?

Some parts of pmm which involve pictures or videos of children, can only be viewed by registered users. Registering also allows you to bookmark favourite pages and track your viewing.

find out more

pmm for you

Please help us ensure pmm is as useful to you as possible by completing this short survey

complete survey