Antibodies in blood samples and biomarkers 4.17/5 (12)

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Antibodies in blood samples can determine the diagnosis

False positive blood test results

Antibody in blood samples occurs by systemic connective tissue disorders og Vasculitis and can be useful when making a diagnosis. These samples are ordered at the laboratory based on clinical suspicion of the current disease. Unfortunately, the tests often show changes even though disease is not present (false positive results). The test results are often answered with results in titres. High titers are more susceptible to disease than low titers.

  • A population study from northern Italy clearly showed elevated antinuclear antibody (ANA in titer 1: 160) in 8,2% of women and 3,7% of men. Most of these are unlikely to be ill or become ill (reference: Selmi C, 2016)
  • The result of the antibody samples must therefore be interpreted with caution, especially at low values

Hepatitis, Rheumatic Disease and Antibody

Some Autoimmune diseases and associated antibodies

Antifosfolipid Syndrome (ApLs)

Antibodies are detected at least twice at least 3 months apart to exclude random, transient results (false positives). Results in high titers and IgG antibodies are most important. People who have rash in all three types (lupus anticoagulant + cardiolipin + betaXUMUM glycoprotein) clearly have the highest risk of blood clots and spontaneous abortions.

Antisynthetase syndrome

MCTD (mixed connective tissue disease)

Myositis and dermatomyositis

Literature: Betteridge ZE, 2011

Myositis Specific Antibody: (Immunological Laboratory OUS by appointment):

Rheumatoid arthritis (RA), arthritis

SLE (Systemic Lupus Erythematosus)

Sjögren's syndrome

Systemic sclerosis (scleroderma)


  • Soluble IL-2 receptor  (sCD25) is a marker for lymphocyte activation and can be obtained from the Immunological lab Oslo University Hospital. Soluble IL-2 receptor is included in diagnostic criteria macrophage activation syndrome High values ​​are expected, but are not specific
    • Increased level of soluble IL-2 receptor also in other inflammatory diseases

Vasculitis diseases

Encephalitis (brain inflammation)

  • GKC complex, mostly LGi1 (face and arm cramps)
  • anti-hu (cranial neuropathy)
  • anti-GBA-b receptor (cramps)
  • anti-GAD65 (Stiff-person Syndrome, New Diabetes I)
  • AMPAR antibody (psychosis)
  • anti-NMDAR (psychosis, cramps)
  • D2R (dystonia)
  • GlyR (hyperplexia, overreaction)
  • GABA -AR (convulsions)
  • Caspr2 (muscle cramps, facials)
  • DPPX (myoclonus, delirium, superficial intestine)
  • Ma2 (cranial neuropathy)
  • Miller-Fisher (cranial neuropathy), (cranial neuropathy)

(Reference: Lancaster E, 2016)

Antibody occurs in serum and in spinal fluid.

Other conditions & antibody:


Monarch PA, 2014 (vasculitis antibody)

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