Spring 2019 (Volume 29, Number 1)
ANA and ANCA Testing in a Tertiary Health Centre in
Sherbrooke:
An Assessment of the Adherence to Guidelines
and the Impacts on the Diagnosis and Health Care System
By Maria Parfenova, MD, FRCPC; and Patrick Liang, MD, FRCPC
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Objectives: To describe antinuclear antibodies (ANA) and
subserology ordering practices and to determine if their
indications meet the recommendations for ANA testing at
the Sherbrooke University Health Centre. To describe antineutrophil
cytoplasmic antibodies (ANCA) testing practices
and determine if they meet the current recommendations
proposed for ANCA testing, at the same centre.
Methods: Patients who had ANA and subserologies (Anti-
SSA, anti-SSB, Anti-Jo1, Anti-Scl-70, Anti-Sm, Anti-U1 RNP)
between 2012 and 2014 were found by means of a computerized
system and their charts were analysed. We identified
the indications for the ANA and subserologies panel in the
medical notes and compared them to the guidelines for ANA
testing and the Choosing Wisely Canada recommendations.
Moreover, the indications for ANCA tests were assessed and
compared to the current guidelines for the appropriate testing
of ANCA and the Choosing Wisely Canada recommendations.
Variables included gender, age, ANA titer, subserologies
panel, indication of ANA, ANCA > 1:20, subtypes MPO
and PR3, indications for ANCA, medical specialty, setting of
the order and the final diagnosis.
Results: There were a total of 268 ANA tests included. In 35.8%
of cases (n=96), ANA was ordered as per recommendations,
versus 63.8% of cases (n=171) without indications. There
were 104 subserologies ordered and 55.8% were ordered at
the same time as the ANA, against the Choosing Wisely Canada
recommendation of 2013. Almost half of the subserologies
ordered had no indications of ANA in the first place (48.1%).
The three medical specialties that ordered ANA the most were
rheumatology, gastroenterology and internal medicine (in
descending order). A total of 134 ANCA tests were included.
Of these, 51.5% were ordered in line with the recommendations,
20.1% not meeting recommendations, and 28.4% for
follow-ups. In fact, 44.4% of those not meeting the recommendations
(n=12) were done because of clinical suspicion of
inflammatory bowel disease or sclerosing cholangitis. Clinical
remission of subjects with ANCA was evident in 100% of cases,
even before ordering the ANCA test for follow-up (negative
predictive value). Only 20% of ANCAs' results influenced the
subsequent management.
Discussion: These results show that the rate of ANA and
ANCA tests ordered in line with the recommendations remains
low. Many ANA subserologies are ordered at the same
time as the ANAs. However, the ANA and ANCA tests that
were ordered without stated recommendations can still
have reasonable indications to be measured in complicated
cases, for example. Moreover, some of the patients that were
hospitalized had ANA and serologies done together to save
time, which is understandable. ANCA can be found in other
non-vasculitic disorders and help the diagnosis for inflammatory
bowel disease, primary sclerosing cholangitis and
autoimmune hepatitis. Taking that into consideration, indications
for these tests should be individualized for a hospitalized
versus an ambulatory patient, and clinical presentation.
The cost for ANA and serologies tests ordered without
suggested indication was more than three thousand dollars
in the time period studied and almost two thousand dollars
for ANCA tests. These costs don’t include indirect costs of
more investigations, more medical consultations, visits and
patients' anxiety.
Conclusion: In summary, too many ANA subserologies are
ordered at the same time as the ANAs. These orders have
an important cost for the health care system that can be
lowered by providing more education for professionals on
avoiding unnecessary tests. Clinical assessment rather than
ANCA testing should guide treatment changes especially
when patients are in remission.
References:
1. Solomon DH, et al. Evidence-based guidelines for the use of immunologic tests: Antinuclear antibody
Testing, Arthritis & Rheumatism. Arthritis Care Res 2002; 47:434-44.
2. Robinson P. and Steele R. Appropriateness of antineutrophil cytoplasmic antibody testing in a
tertiary hospital. J Clin Pathol 2009; 62:743-45.
3. Choosing Wisely Canada 2015. Available at https://choosingwiselycanada.org/rheumatology/.
4. Davis LA, et al. Applying Choosing Wisely: Antinuclear antibody (ANA) and sub-serology testing in
a safe net hospital system. The Open Rheumatology Journal 2015; 9:82-7.
5. McGeoch L. et al. CanVasc recommendations for the management of antineutrophil cytoplasm
antibody-associated vasculitides. J Rheumatol 2016; 43:97-120.
6. Savige J, et al. International consensus statement on testing and reporting of antineutrophil cytoplasmic
antibodies (ANCA). Am J Clin Pathol 1999; 111:507-13.
Maria Parfenova, MD, FRCPC
General Internal Medicine, Department of Medicine
CIUSSS de l’Estrie-Centre Hospitalier Universitaire de Sherbrooke
Université de Sherbrooke, Sherbrooke, Quebec
Patrick Liang, MD, FRCPC
Rheumatology Division, Department of Medicine
CIUSSS de l’Estrie-Centre Hospitalier Universitaire de Sherbrooke
Université de Sherbrooke, Sherbrooke, Quebec
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