Laboratory Tests

A good history and detailed clinical examination of the patient are essential for a proper diagnosis of over 100 types of arthritis. Recognition of patterns of joint involvement (topography) and those of disease presentation and progression is essential for correct clinical diagnosis. In rheumatology practice, a working diagnosis can usually be made on proper examination of the patient. Laboratory tests, including X-Rays, are ordered later to confirm the diagnosis, rule out other possible causes, estimate the level of disease activity, or monitor drug toxicity. As with any other investigations, these must be obtained from a reliable laboratory. The results should always be interpreted in view of the clinical picture. These tests are expensive and must not be used indiscriminately. Laboratory studies are helpful in arthritis only if ordered in an appropriate clinical situation and interpreted accordingly. Measurement errors, laboratory variations due to various factors, and inherent limitations must always be born in mind. A positive test in the absence of an appropriate clinical setting can generally be overlooked.

Commonly used laboratory investigations are discussed below:

Further readings

Haemogram (Complete Blood Count - CBC)

This simple and inexpensive test gives valuable information about anemia (low hemoglobin concentration) and the status of the bone marrow, which manufactures various blood cells. Morphology of red

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Erythrocyte sedimentation rate (ESR)

The liver produces acute phase reactants such as fibrinogen, haptoglobin, alpha-1-antitrypsin, C-reactive, and other proteins in response to inflammation. Interleukin-1, an inflammatory cytokine,

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C-reactive protein (CRP)

CRP, a glycoprotein, is an acute phase reactant by itself and, though costlier than ESR, is a more specific marker of acute inflammation. It elevates within 4 hours of injury and peaks within

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Rheumatoid Factor

Rheumatoid factors are autoantibodies directed against the Fc portion of IgG immunoglobulin. The development of the rheumatoid factor is a mechanism to help remove immune complexes from

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Anticyclic Citrullinated Peptide Antibodies (ACPA)

ACPA are antibodies found to be associated with RA. They are reported to be highly specific (98%) and moderately sensitive (70%) for RA. They predict an erosive disease. These antibodies can

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Anti-Streptolysin O (ASO)titre

This test is directed against extracellular products found in the supernatant broth of culture of bacteria called streptococci. ASO titer test should be ordered only when the diagnosis of acute

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Uric acid

Gout is the most common cause of inflammatory arthritis in men over 40 years of age. It usually affects the joint at the base of the great toe. The onset of arthritis is abrupt with exquisite

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LE cell phenomenon

LE cell phenomenon is an outdated test and should never be

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Anti-nuclear antibodies (ANA)

ANA are a diverse group of autoantibodies positive in about 30% of cases of RA. These patients have more severe disease and poorer prognosis. Arthritis due to other systemic autoimmune diseases

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Anti ds-DNA Antibodies

This test is helpful in confirmation of the diagnosis of systemic lupus erythematosus. Moreover, it indicates the activity of SLE as well as kidney disease in SLE. It should ideally be done by the

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HLA B27

HLA B27, a commonly misinterpreted test, is a genetic marker usually present in 8-10% of the average population. The diagnosis of ankylosing spondylitis (AS) and other spondarthritides needs to be

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Liver Function Tests

These are often ordered to assess the preliminary status and monitoring toxicity due to drugs like methotrexate, sulphasalazine, and azathioprine. Serum protein estimation indicates appropriate

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Kidney function Tests

These are ordered to assess the baseline status and monitoring toxicity or dose adjustments of some drugs such as pain killers. Simple tests such as urine examination, blood urea, and serum

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Synovial fluid examination

Examination of fluid aspirated from a swollen joint is invaluable in diagnosing inflammatory, septic, and crystal-induced arthritis as well as haemarthrosis (blood in a joint). Fluid must be

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Imaging Techniques

X-rays help detect bone erosions and other changes for the diagnosis of arthritis. There are many different situations where X-Rays of various body parts may be required. Obtaining appropriate

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Arthritis- Incidence and Measures (Abridged)
संधिवाताचा हत्ती
Why Rheumatology?
ह्रुमॅटॅालॅाजी कशासाठी?
Arthritis – Introduction
संधिवाताची ओळख
Osteoarthritis
झिजेचा संधिवात
Rheumatoid Arthritis
आमवाताची सूज
Gout
गाउट - विंचू चावला हो
Chikungunya Arthritis
चिकुनगुन्या
Back pain
पाठ दुखी
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©2023 arthritis-india.com | designed & developed by SSPL