Lab findings & conditions resulting in Polyarticular Joint Pain

February 20,2021
5 Min Read

This list is to be viewed only in the context of evaluation of patients with polyarticular joint pain.

Laboratory or Imaging Tests		Condition(s)
Complete Blood Count (CBC)	Anemia	Many inflammatory arthritides, especially SLE, RA, IBD and human parvovirus B19 infection
	Polycythemia	Myeloproliferative disorder
	Thrombocytopenia	SLE, human parvovirus B19 infection
	Thrombocytosis	Acute-phase reaction, vasculitis, infection
	Leukopenia	SLE, RA, Felty's syndrome, Sjogren's syndrome, human parvovirus B19 infection Leukocytosis RA, vasculitis, reactive arthritis, infection
	Absolute Lymphocytosis	CLPD (polyarthritis can be one of the components of clinical manifestation)
	Eosinophilia	SLE, RA, IBD, sarcoidosis, dermatomyositis, scleroderma, Churg-Strauss syndrome, PAN, eosinophilic fasciitis, cholesterol emboli
Chest X-Ray	Infiltrates or Nodules Serositis Upper Lobe Fibrosis	RA, sarcoidosis, Wegener's granulomatosis, Churg-Strauss syndrome SLE, RA Ankylosing spondylitis
Chest X-Ray	Diffuse Fibrosis	RA, Scleroderma, Polymyositis
Joint Aspiration	Growth on culture	Infection
	Crystals	Gout, Pseudogout
	WBC Count	>2000/mm3 — Inflammation > 50000/mm3 — Probable infection
Urinalysis	Hematuria	SLE, Wegener's granulomatosis, PAN
	Pyuria	Reactive polyarthritis (due to UTI)
	Proteinuria	SLE; Wegener's granulomatosis, amyloidosis
ECG	Atrioventricular Block	Lyme disease, neonatal lupus, ankylosing spondylitis
APTT/Lupus anticoagulant/APLA	Prolonged/Present	SLE, APLA Syndrome
Rheumatoid Factor		RA, SLE, Sjogren's syndrome, sarcoidosis, reactive arthritis, PMR, polymyositis, psoriatic arthritis, endocarditis, chronic infections, cancer, chronic liver disease, many nonrheumatic causes
Anti-CCP Antibody		RA
Inflammatory markers		Infection, most inflammatory arthritides, advanced age, PMR, giant cell arteritis, cancer, anemia, pregnancy; menses
Antinuclear Antibody		SLE, RA, scleroderma, Sjogren's syndrome, vasculitis, polymyositis, medications, many nonrheumatic causes
Elevated SGOT/SGPT		SLE, PAN, sarcoidosis, hemochromatosis, Sjogren's syndrome, infectious hepatitis, polymyositis
Elevated ALP		Bone metastases, Paget's disease, osteomalacia, PMR, ankylosing spondylitis, hyperparathyroidism
Elevated LDH		Autoimmune hemolytic anemia, myositis
dsDNA		SLE, especially lupus nephritis
Anti SS-A/Ro, Anti SS-B/La		Sjogren's syndrome, SLE
HLA-B27		Spondyloarthropathies, reactive arthritis
Elevated Uric Acid		Gout, psoriatic arthritis, Paget's disease
False-Positive VDRL		SLE, APLA Syndrome
c-ANCA		Wegener's granulomatosis
Elevated Creatinine		SLE, Wegener's granulomatosis, vasculitis
Elevated Creatine Kinase (CPK)		Polymyositis, dermatomyositis, hypothyroidism
Elevated Calcium		Hyperparathyroidism, cancer, sarcoidosis

RA: Rheumatoid Arthritis, SLE: Systemic Lupus Erythematosus, IBD: Inflammatory Bowel Disease, CLPD: Chronic Lymphoproliferative Disease, PAN: Polyarteritis Nodosa, UTI: Urinary Tract Infection, APLA: Anti Phospholipid Antibody

References:

Alpay-Kanitez N, celik S, Bes C. Polyarthritis and its differential diagnosis. Eur J Rheumatol. 2019 Nov 11;6(4):167-73.
Mies Richie A, Francis ML. Diagnostic approach to polyarticular joint pain. Am Fam Physician. 2003 Sep 15;68(6)1151-60.