TEST DIRECTORY... | MIDx Labs

- PROFILE - JOINT (ARTHRITIS) EVALUATION

The Joint (Arthritis) Evaluation Profile provides the serologic and inflammatory assessment used in the initial workup of undifferentiated joint pain, and establishes the baseline organ function required before initiation of anti-inflammatory or disease-modifying therapy. ESR and CRP quantify systemic inflammation and are complementary rather than redundant; CRP responds within hours and falls quickly, while ESR reflects a longer interval and is useful in tracking chronic disease activity.

Rheumatoid factor and anti-cyclic citrullinated peptide antibody assess for rheumatoid arthritis, with anti-CCP carrying substantially greater specificity and predicting erosive disease. Antinuclear antibody screens for connective tissue disease. Uric acid supports the assessment of gout. Ferritin is included both as an acute-phase reactant and for the marked elevation characteristic of adult-onset Still's disease. Comprehensive metabolic panel and CBC with automated differential establish renal, hepatic, and hematologic baselines, and Vitamin D is assessed as a contributor to diffuse musculoskeletal pain.

Intended for adults presenting with polyarticular joint pain, morning stiffness, joint swelling, or suspected inflammatory arthritis. This profile is a serologic evaluation and does not substitute for joint aspiration. Acute monoarticular arthritis with a hot, swollen joint requires urgent arthrocentesis to exclude septic arthritis; serologic testing must not delay that assessment.

LIS PROFILE CODE: (MID) Joint (Arthritis) Evaluation Profile

INDIVIDUAL LIS TEST/PANEL CODES INCLUDED WITHIN PROFILE: (MID) Comprehensive Metabolic Panel (CMP), (MID) Complete Blood Count with Automated Differential (CBCWD), ESR, CRPWR, RF, ACCP, ANA, URIC, FERR, VITD

CPT CODE: 80053 (CMP) + 85025 (CBCWD) + 85652 (ESR) + 86140 (CRP) + 86431 (RF) + 86200 (ACCP) + 86038 (ANA) + 84550 (URIC) + 82728 (FERR) + 82306 (VITD)

NOTE: This is a MID-defined profile, not an AMA-recognized panel; components are billed individually and each must be supported by documented medical necessity for the individual patient. Reflex components are billed separately when performed, see Special Instructions.

ALIASES: Arthritis Panel, Joint Pain Workup, Rheumatology Screening Profile, Inflammatory Arthritis Evaluation

METHODOLOGIES: Spectrophotometry, Ion-Selective Electrode (ISE), Immunoturbidimetry, Chemiluminescent Microparticle Immunoassay (CMIA), Indirect Immunofluorescence Assay (IFA), Enzyme Immunoassay (EIA), Hydrodynamic Impedance, Laser-Based Flow Cytometry, Sodium Lauryl Sulfate (SLS) Hemoglobin, Automated Westergren (Excyte Mini)

SPECIMEN:

- Type: Serum & Whole Blood

- Container: 2 Gold Top (SST) Vacutainers & 1 Lavender Top (K2/K3 EDTA) Vacutainer

- Minimum Volume Required: 2 mL for each container.

- Order of Draw: Gold Top (SST) before Lavender Top (K2/K3 EDTA) per CLSI GP41.

- Storage/Handling:

Gold Top (SST) Vacutainer - Allow 30 minutes for blood to clot, then centrifuge specimen at 3500 RPM for 10 minutes. Maintain specimen at room temperature or in the refrigerator until testing can be performed.

Lavender Top (K2/K3 EDTA) Vacutainer - Gently invert specimen 8 - 10 times immediately following blood collection to prevent clotting. Maintain specimen at room temperature or in the refrigerator until testing can be performed.

- Stability:

Room Temperature (20-25 °C): 2 hours

Refrigerated (2-8 °C): 2 days (please note however that cellular degeneration can occur as soon as 24 hours post-collection)

Frozen (-20 °C or colder): Not Accepted

- Turnaround Time: 24 - 48 hours from receipt.

Special Instructions: Specimens meeting predefined criteria (e.g., flagged morphologic abnormalities, significant differential shifts, or critical count thresholds) will automatically reflex to a peripheral blood smear review by a medical laboratory scientist at no additional charge.

Depending on the findings identified on smear review, the specimen may be further escalated to pathologist for final interpretation, and any additional testing will be added to the original order.

Reflex testing. A positive ANA screen reflexes to titer and pattern. Anti-dsDNA, extractable nuclear antigen antibodies, and complement C3/C4 are performed only on a positive ANA in the presence of clinical features consistent with connective tissue disease, and are billed separately. ANA has limited specificity and should not be treated as a diagnostic test. A positive ANA at low titer occurs in a substantial proportion of healthy individuals and rises with age. In undifferentiated joint pain without clinical features of connective tissue disease, a positive result is far more likely to represent a healthy variant than disease. ANA sub-serologies should not be ordered without both a positive ANA and clinical suspicion of immune-mediated disease.

Rheumatoid factor also lacks specificity. It is detectable in healthy older adults and in hepatitis C, Sjögren's syndrome, endocarditis, and chronic infection. Anti-CCP antibody carries substantially greater specificity for rheumatoid arthritis and better predicts erosive disease; discordant results should be interpreted with weight given to anti-CCP.

Serum uric acid neither confirms nor excludes gout. Uric acid is normal or low in a substantial minority of patients during an acute flare, as urate deposits into the joint, and asymptomatic hyperuricemia is common in patients who never develop gout. Definitive diagnosis requires identification of negatively birefringent monosodium urate crystals on synovial fluid examination under polarized light.

This profile does not exclude septic arthritis. An acutely hot, swollen, painful joint requires urgent arthrocentesis with synovial fluid cell count, Gram stain, culture, and crystal examination. Normal inflammatory markers do not exclude joint infection, and serologic testing must not delay aspiration.

ESR and CRP are both suppressed by corticosteroid therapy. Normal values in a patient on steroids do not exclude active inflammatory disease. Ferritin is an acute-phase reactant and rises with inflammation independently of iron status. A markedly elevated ferritin, particularly above several thousand ng/mL with fever and rash, should prompt consideration of adult-onset Still's disease or hemophagocytic lymphohistiocytosis. CRP in this profile is standard-sensitivity CRP (86140). It is not interchangeable with high-sensitivity CRP (86141) for cardiovascular risk stratification.

Lyme serology is not included in this profile. Order separately where an intermittent or persistent monoarthritis, most often of the knee, is accompanied by documented tick exposure or compatible clinical findings.

REJECTION REASONS: Clotted Specimen, QNS, Gross Hemolysis, Gross Lipemia, Contamination, Stability Violation, Expired Container, Incorrect Container

REFERENCE RANGES:

Please refer to individual test/panel directory pages for reference ranges for each test/panel included.