untangling rheumatology bloodwork...ana testing • an ana titre of

Untangling Rheumatology Bloodwork

Dianne P Mosher, MD, FRCPCProfessor, Department of Medicine

Associate Dean, Community Engagement and Strategic PartnershipsCumming School of Medicine, University of Calgary

Section Chief, Division of Rheumatology

Faculty/Presenter Disclosure

• Faculty: Dr. Dianne Mosher• Relationships with financial sponsors:

• Grants/Research support: N/A• Speakers Bureau/Honoraria: AbbVie, Merck, Novartis, Pfizer, Sandoz, UCB• Consulting Fees: AbbVie, Merck, Novartis, Pfizer, Sandoz, UCB• Patents: N/A• Other: The Alberta College of Family Physicians has provided support in the form of speaker fees and/or expenses.

Copyright

• I have taken the appropriate steps to ensure that the use of third party material in this presentation falls under fair dealing in the Copyright Act. https://library.ucalgary.ca/copyright/

• This material was created for those enrolled in the Family Medicine Summit and cannot be reproduced, retransmitted or copied.

• I have properly cited third party material in one of the ways outlined below.

By the end of this session you should be able to:

• List the variables that influence the interpretation of a clinical test• Understand factors that influence the interpretation of inflammatory markers• Understand referral pathways and requirements• Understand common rheumatology tests and their utility• Be aware of Choosing Wisely recommendations • Be aware of the potential for biomarker testing

Outline• Lab testing principles• Acute phase reactants• RF/Anti CCP• ANA• ANCA• Antiphospholipid antibodies• HLA B27• Future Directions

Pre-test Probability Post-test Probability

Test

↑Sensitivity ↑Specificity

N Range 1 N Range 2

Slide courtesy Dr. Volodko Bakowsky

HLA B27

• 95% sensitive, 95% specific for Ank Spond• Likelihood ratio up to 24• Present in 8% of Caucasian population• Ank Spond prevalence 1 in 500


Test + Test -Ank Spond 18 2 20No Ank Spond

499 9481 9980

PPV = 18/18+499 = 3.5%

NPV = 9481/9481+2 = 99.9%

Testing in Random 10,000 People


Test + Test -Ank Spond 950 50 1000No Ank Spond

450 8550 9000

PPV = 950/950+450 = 68%

NPV = 8550/8550+50 = 99%

Increase Prevalence to 10%


Case• 32 y.o. woman • 6 weeks post partum• New onset of pain in her joints: describes swelling in

• PIPs • MCPs• Knees• MTP joints

• Marked fatigue and stiffness lasting several hours in the morning

Case

• PMHx – negative• Meds – none

Case

• Vitals normal• Tenderness of PIP and MCPs but no obvious synovitis• Labs: CBC normal, CRP normal, RF 26, anti CCP high positive and ANA 1/80

Referral Requirements for Suspected Inflammatory Arthritis – Path to Care• Reason for Referral• Detailed History to support the Referral

• Physical Exam to support the Referral• Medication List• Describe symptoms; description of joints involved, swelling, pain, morning stiffness, duration

• Describe previous treatments and responses; specifically with Prednisone

• CBC, CRP, Creatinine• ALT/ALK Phos• Anti CCP if applicable• RF if applicable• Uric acid if applicable

Referral Requirements Suspected Autoimmune Disease – Path to Care• Reason for Referral• Detailed History to support the Referral

• Physical Exam to support the Referral• Medication List• Describe symptoms; description of joints involved, swelling, pain, morning stiffness, duration

• Describe previous treatments and responses; specifically with Prednisone

• CBC, CRP, Creatinine• ALT/ALK Phos• Urinalysis• C3, C4• ANA

www.specialistlink.ca

Peripheral Arthritis Pathway

Common Laboratory Tests

• Acute Phase Reactants• Rheumatoid Factor/antiCCP• ANA • C3,C4• ANCA• HLA B27

Acute Phase Reactants

• Positive• ESR• CRP• Haptoglobin• Complement proteins• Platelets

• Negative• Albumin• Transferrin• Hemoglobin

ESR

X mm---

RBC

Plasma


ESR

• Gum Up Negative Charges• Fibrinogen ↑• Immunoglobulins ↑• Renal Failure ↑• Pregnancy ↑• Obesity ↑

• Abnormalities of Red Blood Cells• Anemia* ↑• Polycythemia * ↓• Sickle Cell Anemia ↓

ESR: Estimation of Upper Level of Normal

2

Age (years) +10 (if female)

CRP

• Direct acute phase reactant• Levels change more quickly than ESR• Less subject to artefact• Can be elevated in obesity

Rheumatoid Factor

• IgM Antibody directed to Fc Portion of IgG• Rheumatoid Factor (RF) is commonly associated with rheumatoid arthritis

• Sensitivity 66%,specificity 82%• It is also associated with many other diseases such as Sjogren’s Syndrome, cryoglobulinemia (HCV), infectious diseases and malignancy

Anti CCP Antibody/ACPA• Autoantibody found in patients with Rheumatoid Arthritis• 70% sensitive, 95% specific for RA• A positive anti‐CCP/ACPA significantly increases the probability of rheumatoid arthritis

• It predicts more aggressive, erosive disease and is useful to triage patients.

• Anti‐CCP/ACPA may be present up to 10 years prior to diagnosis

ANA Testing• It is used to screen for autoimmune disease

• Systemic• SLE, Systemic Sclerosis• Sjogren’s Syndrome• Juvenile Idiopathic Arthritis: identify patients at risk of developing uveitis

• Organ specific• Autoimmune hepatitis• Hashimoto’s thyroiditis

• It is used to categorize what type of systemic autoimmune disease• It may be helpful to establish prognosis

ANA Testing

• An ANA titre of

ANA Patterns Centromere: CENP

Nucleolar

Current ANA • ANA screen

• ds DNA → Lupus• Ribosomal P → Neuropsychiatric Lupus• Ro → Lupus and Sjogren’s• La → Lupus and Sjogren’s• Centromere → Limited Cutaneous Scleroderma• Sm → Lupus• RNP → Lupus and Mixed CTD• Scl‐70 → Diffuse Scleroderma• Jo‐1 → Polymyositis

SARD (SLE, SSc, MCTD, AIM, SjS)

are complex conditions exemplified by heterogenous clinical and pathological phenotypes

SLE – a variety of signs & symptoms…

© Hinchcliff & Varga. Am. Fam. Phys. 15:971, 2008& Slide collection of American College of Rheumatology

*

SSc – a spectrum of signs & symptoms…

Snapshot of Autoantibodies in AARDSLE* Scleroderma Sjögren’s

SyndromeAIM Vasculitis

dsDNAchromatin

Ribosomal P

CENP-A,-Btopoisomerase I

(Scl-70)

SS-A/Ro 60SS-B/La

M3 receptor

Jo-1+ other aa tRNA

synthetases

PR3MPO

snRNPs (Sm, U1-6 RNP)

C1q

RNA Pol I/IIIPM/SclBICD2

SS-56Golgins

GW Bodies

PM/SclKu

p155/TIF1

ElastaseLAMP-2

Lysozyme

SS-A/Ro60Cardiolipin -2 GP1PCNA/proteasome

Fibrillarin (U3RNP)PDGF-R

Exosome

CENP-C ?-fodrin

Mi-2MDA5

HMGCR

BPIAzurocidinLactoferrin

NMDA/NR 2 receptorPhospholipase A2R

To/ThB23/numatrin

NuMATS-1 RNA

SRPSMN/gemins

SFPQ

DefensinsEEA-1

Ro52/TRIM21 TRIM 21/Ro52 TRIM21/Ro52 TRIM21/Ro52 ? — ?DFS70 DFS70 DFS70 DFS70 DFS70

Slide courtesy of Dr. M. Fritzler

ANA Testing is widespread … and growing

• ANA testing rate varies from 1/40/population/yr to 1/500/population/yr.

• Calgary region: 1/40/population (2.2 M)• = 50,000 ANA tests/year• 70% are ordered by primary care

• Question: What proportion of Albertans see a physician every year?• Answer: ~84%

• Consensus: ~20% of all ANA IIF tests are positive• In Calgary region this = ~10,000 +ve tests/year• However, only ~5,120 are referred to Calgary rheumatologists every year

• What happened to the other 5,000???


Choosing Wisely – Canadian Rheumatology Association

• ANA testing should not be used to screen subjects without specific symptoms (e.g., photosensitivity, malar rash, symmetrical polyarthritis, etc.) or without a clinical evaluation that may lead to a presumptive diagnosis of SLE or other CTD, since ANA reactivity is present in many non‐rheumatic conditions and even in “healthy” control subjects (up to 20%).

• In a patient with low pre‐test probability for ANA‐associated rheumatic disease, positive ANA results can be misleading and may precipitate further unnecessary testing, erroneous diagnosis or even inappropriate therapy.

https://choosingwiselycanada.org/rheumatology/

ABIM Choosing WiselyGuidelines CHOOSING WISELY (ACR/CRA)• “ANA should not be used as a screening test in patients presenting with fatigue, myalgia or

nonspecific symptoms.”

Yazdany, et al. Choosing wisely: the American College of Rheumatology's Top 5 list of things physicians and patients should question. Arthritis Care Res.(Hoboken.). 65:329‐339, 2013.

Chow, et al.. Choosing Wisely: The Canadian Rheumatology Association's List of 5 Items Physicians and Patients Should Question. J. Rheumatol. 42: 682, 2015.

Aryeh M. Abeles, MD, Micha Abeles, MDDivision of Rheumatology, University of Connecticut Health Center, Farmington.

The most common reason for ordering ANA testing was widespread pain (54/232, 23.2%).

CONCLUSIONS: In this retrospective study, more than 90% of patients who were referred to a tertiary rheumatology clinic for a positive ANA test result had no evidence for an ANA‐associated rheumatic disease. The poor predictive value of a positive ANA in this cohort was largely attributable to unnecessary testing in patients with low pretest probabilities for ANA‐associated rheumatic disease.

The American Journal of Medicine (2013) 126, 342‐348


Central Triage3 Year Audit

Total ReferralsN=15,357

Referral Profile

Inflammatory Arthritis26%

Arthralgias3%

Other8%

Osteoarthritis6%

Soft Tissue Rheumatism

3%

Autoimmune Disease12%

Crystal Arthropathy

3%

Positive ANA/ENA

4.2% (N=643)

Vasculitis2%

Spondyloarthritis4%

Foothills Medical Center Evaluation1.7% (N=263)

Central Triage “CReATe” Derivation of ANA+ Cohort

© Fitch-Rogalsky C, et al. PLoS ONE 9:e93812, 2014

ANCA: Historically Pattern and Titer

Current ANCA• Anti PR3

• Granulomatosis Polyangiitis (GPA)• Upper airway and sinus involvement• Palpable purpura• Pulmonary‐renal syndrome

• Anti MPO• Microscopic Polyangiitis (EGPA)

• Similar to Wegener’s but no upper airway involvement• Eosinophilic Polyangiitis

• Small vessel vasculitis + asthma + eosinophilia

Antiphospholipid Antibodies

• Anticardiolipin• Beta2 glycoprotein• Lupus Anticoagulant

Antiphospholipid Antibodies

• Arterial thrombosis• Unusual or recurrent venous thrombosis• Recurrent miscarriages• Supportive evidence for lupus

HLA B27 and Choosing Wisely• HLA‐B27 testing is not useful as a single diagnostic test in a patient with low back pain without further spondyloarthropathy (SpA) signs or symptoms (e.g., inflammatory back pain ≥3 months duration with age of onset

Bandwidth of autoantibody testing is changingAE: autoimmune encephalitisALD: autoimmune liver diseaseAPS: anti‐phospholipid syndromeGN: glomerulonephritisIIM: idiopathic myopathiesILD: interstitial lung diseaseNPLE: neuropsychiatric LEMCTD: mixed conn. tissue dis.OS: overlap syndromesSACLE: sub‐acute cutaneous LESjS: Sjogren’s syndromeSSc: systemic sclerosisUCTD: undifferentiated CTD

© Fritzler MJ. J Rheumatol Res 1: 10-18, 2019

TIME COURSE SARD

CLINICALPRE‐CLINICALINDUCTION

ORGAN DAMAGE

None MinimalProgressive Change

Symptomatic

GENETICS

TRIGGER FACTORS

PATHOGENIC MEDIATORS

CONTEMPORARY MEDICINE:INTENT TO TREAT

FUTURE MEDICINE:INTENT TO PREVENT

Autoantibodies: increase in number, titer, epitope spreading and other characteristics.


Our Case

• Diagnosis: pre‐RA? • I would see her in consult• Definitely would order ANA but also urinalysis

Summary• List the variables that influence the interpretation of a clinical test

• Pretest probability ie prevalence• Sensitivity and specificity of test

• Understand factors that influence the interpretation of inflammatory markers

• Pretest probability• Systemic inflammation vs multiple other factors

• Understand tests required for referral and why• Interpretation of antibody testing and future directions

Thank you!

untangling rheumatology bloodwork...ana testing • an ana titre of

Documents