Psoriatic arthritis laboratory tests

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Chandrakala Yannam, MD [2]

Overview

There are no specific diagnostic laboratory findings associated with psoriatic arthritis. There are certain blood tests that can check for markers of inflammation. Patients with psoriatic arthritis are usually tested for the gene associations includes HLA-B27, HLA-C*06, rheumatoid factor, and autoantibodies. Other laboratory findings consistent with psoriatic arthritis include CBC, ESR and CRP levels, and synovial fluid analysis.

Laboratory Findings

There are no specific laboratory findings associated with psoriatic arthritis and most the tests are non-specific.
However, there are certain laboratory tests that can check for markers of inflammation and to exclude other diseases. These include:^[1]
- CBC with differential count
  - Leukocytosis
  - Anaemia
- Elevated ESR
- Elevated CRP (C- reactive protein)
- Autoantibodies: The following autoantibodies may be found in patients with psoriatic arthritis.^[2]
  - Rheumatoid factor
  - ANA (Antinuclear antibodies)
  - Anti-citrullinated peptide antibodies (ACPA)
- Genetic markers:^[3]^[4]
  - HLA-B27
  - HLA-C*06
- Synovial fluid analysis: Elevated WBC count suggestive of inflammation.

References

↑ Punzi L, Podswiadek M, Oliviero F, Lonigro A, Modesti V, Ramonda R, Todesco S (2007). “Laboratory findings in psoriatic arthritis”. Reumatismo. 59 Suppl 1: 52–5. PMID 17828345.
↑ Johnson SR, Schentag CT, Gladman DD (May 2005). “Autoantibodies in biological agent naive patients with psoriatic arthritis”. Ann. Rheum. Dis. 64 (5): 770–2. doi:10.1136/ard.2004.031286. PMC 1755477. PMID 15834057.
↑ Chandran V, Bull SB, Pellett FJ, Ayearst R, Rahman P, Gladman DD (October 2013). “Human leukocyte antigen alleles and susceptibility to psoriatic arthritis”. Hum. Immunol. 74 (10): 1333–8. doi:10.1016/j.humimm.2013.07.014. PMID 23916976.
↑ Eder L, Chandran V, Pellet F, Shanmugarajah S, Rosen CF, Bull SB, Gladman DD (January 2012). “Human leucocyte antigen risk alleles for psoriatic arthritis among patients with psoriasis”. Ann. Rheum. Dis. 71 (1): 50–5. doi:10.1136/ard.2011.155044. PMID 21900282.

Overview