Frequency of Repeating Antinuclear Antibody Testing: When Less Is More

Area of Science:

• Clinical immunology
• Autoimmune diseases
• Diagnostic testing

Background:

• Antinuclear antibodies (ANA) are crucial for diagnosing autoimmune connective tissue diseases.
• ANA tests exhibit high sensitivity but low specificity, leading to potential misinterpretation and overuse.
• Elevated ANA levels can occur in healthy individuals and non-rheumatologic conditions.

Purpose of the Study:

• To retrospectively evaluate the frequency and appropriateness of repeated ANA testing in adult patients in Saudi Arabia.
• To identify factors associated with inappropriate ANA test ordering and repetition.
• To analyze the impact of repeat ANA testing on clinical management and costs.

Main Methods:

• Retrospective analysis of 40,634 adult patients and 229,825 ANA tests from 2018-2022 in a Saudi Arabian academic hospital.
• In-depth review of a random sample of 500 patients and 998 ANA tests.
• Descriptive and analytical statistics were used, with statistical significance set at p < 0.05.

Main Results:

• 57% of ANA tests were positive, with mild positivity common at 1:80 and 1:160 titers.
• Only 11% of repeated ANA tests were deemed appropriate.
• Repeat testing rarely altered results, especially for moderate to strong positive ANA tests; seroconversions were mainly from negative or weakly positive results.

Conclusions:

• The high rate of inappropriate repeat ANA testing in Saudi Arabia necessitates a re-evaluation of current clinical practices.
• The cost-effectiveness of repeat ANA testing and potential for unnecessary interventions should be carefully considered.
• Further research across diverse healthcare settings in Saudi Arabia is recommended to validate these findings.