Download Rheumatoid Arthritis

RHEUMATOID
ARTHRITIS
Rheumatoid arthritis
Rheumatoid arthritis (RA) affects an estimated 1.5 million people in the United States.1 RA is the most common type of autoimmune
arthritis. Treatments have improved greatly and help many of those affected. For most people with RA, early diagnosis and
treatment can control joint pain and swelling, and lessen joint damage. LabCorp offers a variety of tests to aid in diagnosis,
management of treatment and monitoring of disease activity.
Diagnosis
Early diagnosis of RA is important, because it has been recognized that early initiation of disease-suppressing therapy may improve
clinical outcomes and reduce the accrual of joint damage and disability.2 In 2010, the American College of Rheumatology/European
League Against Rheumatism approved new classification criteria to identify patients at high risk for RA symptom persistence or
structural damage.2 The criteria for diagnosing RA patients, which are presented in the table on the back, include a scoring method
that is based upon the number and types of joints affected, the duration of symptoms, and the results of four laboratory screening
tests. Patients whose cumulative score from each of the categories is six or greater are categorized as having “definite RA.”2
LabCorp’s RA Expanded Profile includes the serological markers (rheumatoid factor and anticitrullinated protein antibody) and
acute-phase reactants (C-reactive protein and erythrocyte sedimentation rate) used to establish the ACR/EULAR classification
criteria. Additionally, LabCorp’s anticitrullinated protein antibody (anti-CCP) offers greater sensitivity than earlier CCP tests and has
been shown to correctly identify 83% of RA patients who were found to be RF negative.3
Test Name
Test No
Rheumatoid Arthritis (RA) Expanded Profile
Profile includes:* Anti-CCP 3.1, C-Reactive Protein (CRP), Quantitative, Rheumatoid Arthritis (RA) Factor,
Sedimentation Rate, Modified Westergren
164245
Rheumatoid Arthritis (RA) Profile
Profile includes:* Anti-CCP 3.1, Rheumatoid Arthritis (RA) Factor
164065
*Individual components may be ordered separately.
Monitoring Disease Activity
Laboratory testing is available to aid in the assessment of disease activity. Crescendo Bioscience’s test, Vectra® DA (Test no.
819290), is available for ordering through LabCorp. Vectra DA assesses disease activity in adult rheumatoid arthritis (RA) patients.
It provides a score, ranging from 1 to 100, that assesses RA disease activity, and is used to categorize the activity as low, moderate
or high. This quantitative method can be used over time to track the progression of disease activity within RA patients. No kits
are necessary for this test. Vectra DA is available for physicians to order through the standard LabCorp ordering process and
collection can take place at LabCorp patient service centers. Additionally, reports will be delivered through the standard results
delivery process for LabCorp.
Please note that LabCorp contracts do not apply as Crescendo Bioscience will continue to perform testing and billing for Vectra DA.
Management of Treatment
Although treatment is multifaceted, medications play an important role in patient management. Among the therapy choices physicians
may consider for treatment are disease-modifying anti-rheumatic drugs (DMARDs) and anti-tumor necrosis factor (TNF) drugs.1
DMARDs
One of the most common DMARDs used to treat RA and other
rheumatic conditions is methotrexate (MTX).4 It may help to
decrease the pain and inflammation of arthritis, and may also
help to decrease damage to joints and long-term disability.1
Anti-TNF Therapy
Anti-TNF drugs are a class of drugs that are used to treat
inflammatory conditions such as RA. These drugs may help to
reduce inflammation and limit disease progression in RA, and
several other diseases.
Therapeutic drug monitoring may be helpful as related to
patient compliance, individual pharmacodynamics and
clinical response.5
Serum measurement of anti-TNF drugs and antibodies to the
drug can help characterize patients who maintain versus lose
responsiveness to therapy.8,9
Methotrexate Polyglutamates (MTXpgsRA) Test
• About 30% to 40% of RA patients do not adequately
respond to methotrexate treatment.6
• A test indicating whether or not a patient has achieved an
expected therapeutic level on a specific dosage protocol can
be useful in ongoing patient management.
• It is considered important to work to attain dose
optimization when treating patients on methotrexate.7
• Testing may be ordered at any time during therapy and
should be conducted at least 36 hours after last dose of
methotrexate.
• The test report includes a measure of each polyglutamate
species, along with interpretive guide.
Adalimumab, Etanercept, Infliximab, and Rituximab
Concentrations and Antibody Tests
• Monitors drug concentration levels to help physicians
optimize dosing and frequency of treatment.
• Identifies those patients who fail therapy or have
diminished response as a result of development of an
antibody to the drug.
• Routine pre-testing treatment of antibody test samples
reduces drug interference and provides clinically valid
antibody results at drug levels well above treatment
targets for Adalimumab, Etanercept, Infliximab, and
Rituximab.10,11,12,13
• Testing may be ordered at anytime during therapy.
Test Name
Test No
Methotrexate polyglutamates
504104
Adalimumab Concentration and Anti-Adalimumab Antibody (Serial Monitor)
503890
Etanercept Concentration and Anti-Etanercept Antibody
504245
Infliximab Concentration and Anti-Infliximab Antibody (Serial Monitor)
503870
Rituximab Concentration and Anti-Rituximab Antibody
504355
TPMT Genetic Test
504142
TPMT Activity
510750
Thiopurine Metabolites
503800
Superior Service
In addition to our comprehensive rheumatology menu, LabCorp offers numerous service benefits including:
• Broad capabilities in autoimmune testing
• Specialized assays for treatment monitoring
• Multiple connectivity options
• Extensive network of managed care health plans
• More than 1700 patient service centers nationwide
The 2010 ACR-EULAR Classification Criteria For Rheumatoid Arthritis
Target population (Who should be tested?): Patients who 1.) have at least 1 joint with definite
clinical synovitis (swelling)* 2.) with the synovitis not better explained by another disease â€
Classification criteria for RA (score-based algorithm: add score of categories A - D; a score of
≥6/10 is needed for classification of a patient as having definite RA) ‡
Score
A. Joint involvement §
1 large joint ¶
0
2-10 large joints
1
1-3 small joints (with or without involvement of large joints) #
2
4-10 small joints (with or without involvement of large joints)
3
>10 joints (at least 1 small joint) **
5
B. Serology (at least 1 test result is needed for classification) †â€
Negative RF and negative ACPA
0
Low-positive RF or low-positive ACPA
2
High-positive RF or high-positive ACPA
3
C. Acute-phase reactants (at least 1 test result is needed for classification) ‡‡
Normal CRP and normal ESR
0
Abnormal CRP or abnormal ESR
1
D. Duration of symptoms §§
<6 weeks
0
≥6 weeks
1
* The criteria are aimed at classification of newly presenting patients. In addition,
patients with erosive disease typical of rheumatoid arthritis (RA) with a history
compatible with prior fulfillment of the 2010 criteria should be classified as having
RA. Patients with longstanding disease, including those whose disease is inactive
(with or without treatment) who, based on retrospectively available data, have
previously fulfilled the 2010 criteria should be classified as having RA.
†Differential diagnoses vary among patients with different presentations, but may
include conditions such as systemic lupus erythematosus, psoriatic arthritis, and
gout. If it is unclear about the relevant differential diagnoses to consider, an expert
rheumatologist should be consulted.
‡ Although patients with a score of <6/10 are not classifiable as having RA, their
status can be reassessed and the criteria might be fulfilled cumulatively over time.
§ Joint involvement refers to any swollen or tender joint on examination, which
may be confirmed by imaging evidence of synovitis. Distal interphalangeal joints,
first carpometacarpal joints, and first metatarsophalangeal joints are excluded from
assessment. Categories of joint distribution are classified according to the location
and number of involved joints, with placement into the highest category possible
based on the pattern of joint involvement.
¶ “Large joints” refers to shoulders, elbows, hips, knees, and ankles.
# “Small joints” refers to the metacarpophalangeal joints, proximal interphalangeal
joints, second through fifth metatarsophalangeal joints, thumb interphalangeal
joints, and wrists.
** In this category, at least 1 of the involved joints must be a small joint; the
other joints can include any combination of large and additional small joints, as
well as other joints not specifically listed elsewhere (e.g., temporomandibular,
acromioclavicular, sternoclavicular, etc.).
††Negative refers to IU values that are less than or equal to the upper limit
of normal (ULN) for the laboratory and assay; low-positive refers to IU values that
are higher than the ULN but ≤3 times the ULN for the laboratory and assay; highpositive refers to IU values that are >3 times the ULN for the laboratory and assay.
Where rheumatoid factor (RF) information is only available as positive or negative,
a positive result should be scored as low-positive for RF. ACPA = anti-citrullinated
protein antibody.
‡‡ Normal/abnormal is determined by local laboratory standards. CRP =
C-reactive protein; ESR = erythrocyte sedimentation rate.
§§ Duration of symptoms refers to patient self-report of the duration of signs or
symptoms of synovitis (e.g., pain, swelling, tenderness) of joints that are clinically
involved at the time of assessment, regardless of treatment status.
Table reproduced with permission from the American College of Rheumatology/
European League Against Rheumatism.
References
1. Handout on Health: Rheumatoid Arthritis. National Institute of Arthritis and Musculoskeletal and Skin Diseases Website
http://www.niams.nih.gov/health_info/Rheumatic_Disease/default.asp#ra_2 . Accessed February 25, 2014.
2. Aletha D, Neogi T, Silman AJ. 2010 rheumatoid arthritis classification criteria. Arthritis Rheum. 2010;62(9):2569-2581.
3. Szabo Z, Soós L, Lakos G, Sipka S, Szekanecz. Performance of third generation anti-CCP assays. Poster presented at:
Controversies in Rheumatology and Autoimmunity (CDRA); March 10-12, 2011; Florence, Italy.
4. Danila MI, Hughes LB, Brown EE, et al. Measurement of erythrocyte methotrexate polyglutamate levels: ready for clinical
use in rheumatoid arthritis? NIH Public Access.2010;12(5):342-347.
5. De Rotte MCFJ, den Boer E, de Jong PHP, et al. Methotrexate polyglutamates in erythrocytes are assiociated with lower
disease activity in patients with rheumatoid arthritis. AnnRheum Dis. 2013;0:1-7.
6. Goodman S. Measuring methotrexate polyglutamates. Clin Exp Rheumatol. 2010 Sep-Oct; 28 (5 Suppl 61): S24-S26.
7. Smolen JS, Landewe R, Breedveld FC, et al. EULAR recommendations for the management of rheumatoid arthritis with
synthetic and biological disease-modifying antirheumatic drugs: 2013 update. Ann Rheum Dis. 2014;73:492-509.
8. Baert F, Norman M, Vermeire S, et al. Influence of immunogenicity on the long-term efficacy of infliximab in crohn’s disease.
N Engl J Med. 2003;348(7):601-608.
9. Karmiris K, Paintaud G, Norman M, et al. Influence of trough serum levels and immunogenicity on long-term outcome of
adalimumab therapy in crohn’s disease. Gastroenterol. 2009;137:1628-1540.
10. LabCorp internal study. Infliximab (IFX) Antibodies by Electrochemiluminscence Assay.
11. LabCorp internal study. Anti-Adalimumab Antibodies by MSD Electrochemiluminescence Assay.
12. LabCorp internal Study. Anti-Rituximab Antibodies by MSD Electrochemiluminescence Assay.
13. LabCorp internal Study. Anti-Etanercept (Enbrel) Antibodies by MSD Electrochemiluminescence Assay.
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