A 28-year-old woman has had painless oral ulcers and patchy non-scarring hair loss for 3 months. Results: HEp-2 ANA 1:640, homogeneous; WBC 3.2 × 10^9/L (reference 4.0-11.0); platelets 82 × 10^9/L (150-400); C3 0.62 g/L (0.90-1.80); C4 0.21 g/L (0.10-0.40); anti-dsDNA, anti-Sm and antiphospholipid antibodies negative; urine protein normal. She has no fever, arthritis, serositis or neuropsychiatric features, and no drug or infection explains the findings. Using the 2019 EULAR/ACR SLE classification criteria (oral ulcers 2 points, non-scarring alopecia 2, leukopenia 3, thrombocytopenia 4, low C3 or C4 3; classified at 10 points or more), what is her result?

9 points; not classified as SLE

Not scorable: anti-dsDNA is negative

A 52-year-old woman has had Raynaud phenomenon for 3 years and now has puffy fingers, skin thickening limited to the hands and early interstitial lung disease on CT. The laboratory's automated ANA screen, a solid-phase immunoassay containing dsDNA, chromatin, Sm, U1-RNP, SSA (Ro60 and Ro52), SSB, Scl-70, centromere B, Jo-1 and ribosomal P, is negative (ratio 0.3; positive at 1.0 or more). At the rheumatologist's request, HEp-2 indirect immunofluorescence is done: titer 1:1280, with smooth, even staining of the nucleoli and little staining of the rest of the nucleus. What is the best next step?

Test an extended systemic sclerosis antibody profile

Report the ANA as negative, as the screen shows

Repeat the solid-phase screen at a higher dilution

Test anti-dsDNA by Crithidia luciliae IFA

A HEp-2 ANA shows about 10 bright dots in each nucleus, with no dots on the chromosomes of dividing cells. With which disease is this pattern most associated?

Mixed connective tissue disease

A 31-year-old woman with SLE has a deep vein thrombosis. On one sample, anticardiolipin IgG is 62 GPL units and anti-beta-2 glycoprotein I IgG is positive, both above the 99th percentile. To meet the laboratory criteria for antiphospholipid syndrome, the next step is:

Repeat both tests at least 12 weeks later

Test for lupus anticoagulant while on warfarin

Repeat both tests within 1 week

None; one positive result is enough

Autoimmune diseases and ANA patterns

14 DOH Abu Dhabi (HAAD) lab licensing practice questions on Autoimmune diseases and ANA patterns, part of Immunology and Serology. The first 14 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

Question 1 · Hard
A 28-year-old woman has had painless oral ulcers and patchy non-scarring hair loss for 3 months. Results: HEp-2 ANA 1:640, homogeneous; WBC 3.2 × 10^9/L (reference 4.0-11.0); platelets 82 × 10^9/L (150-400); C3 0.62 g/L (0.90-1.80); C4 0.21 g/L (0.10-0.40); anti-dsDNA, anti-Sm and antiphospholipid antibodies negative; urine protein normal. She has no fever, arthritis, serositis or neuropsychiatric features, and no drug or infection explains the findings. Using the 2019 EULAR/ACR SLE classification criteria (oral ulcers 2 points, non-scarring alopecia 2, leukopenia 3, thrombocytopenia 4, low C3 or C4 3; classified at 10 points or more), what is her result?
1. A9 points; not classified as SLE
2. B14 points; classified as SLE
3. CNot scorable: anti-dsDNA is negative
4. D12 points; classified as SLE
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Answer: A · 9 points; not classified as SLE
The ANA of 1:640 meets the entry criterion, so the weighted criteria can be scored. Within each domain only the highest-weighted item counts: oral ulcers and alopecia are both mucocutaneous (2 points), leukopenia and thrombocytopenia are both hematologic (4 points), and the low C3 scores 3 points in the complement domain. The total is 2 + 4 + 3 = 9, below the threshold of 10, so she does not meet the classification criteria at present. Adding every item gives 14, and counting both hematologic items gives 12. A negative anti-dsDNA does not stop the scoring, because SLE-specific antibodies are only one domain, and new features or antibodies that appear later can still be added.
- B: Adding every item ignores the rule that only the highest item in each domain counts.
- C: Only a positive ANA is needed for entry; anti-dsDNA is one optional domain.
- D: Leukopenia and thrombocytopenia share a domain, so only the 4 points count.
Question 2 · Hard
A 52-year-old woman has had Raynaud phenomenon for 3 years and now has puffy fingers, skin thickening limited to the hands and early interstitial lung disease on CT. The laboratory's automated ANA screen, a solid-phase immunoassay containing dsDNA, chromatin, Sm, U1-RNP, SSA (Ro60 and Ro52), SSB, Scl-70, centromere B, Jo-1 and ribosomal P, is negative (ratio 0.3; positive at 1.0 or more). At the rheumatologist's request, HEp-2 indirect immunofluorescence is done: titer 1:1280, with smooth, even staining of the nucleoli and little staining of the rest of the nucleus. What is the best next step?
1. AReport the ANA as negative, as the screen shows
2. BRepeat the solid-phase screen at a higher dilution
3. CTest an extended systemic sclerosis antibody profile
4. DTest anti-dsDNA by Crithidia luciliae IFA
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Answer: C · Test an extended systemic sclerosis antibody profile
A homogeneous nucleolar pattern on HEp-2 cells points to antibodies against nucleolar antigens such as PM/Scl or Th/To, which are linked to systemic sclerosis and its overlap syndromes. None of these antigens is in the solid-phase screen, so the screen cannot detect them, and the strong result by HEp-2 IFA, the reference method, stands. An extended systemic sclerosis line or bead assay that includes PM/Scl, Th/To, fibrillarin and RNA polymerase III identifies the antibody and helps predict organ risks such as lung disease. Dilution cannot make the screen react to an antigen it does not contain, and anti-dsDNA is an SLE marker that does not explain a nucleolar pattern. Laboratories that screen with solid-phase assays should know which antigens they leave out and offer HEp-2 IFA when the clinical picture calls for it.
- A: HEp-2 IFA is the reference method, and a titer of 1:1280 must not be discarded.
- B: The antigen is missing from the panel, so dilution will not make the screen react.
- D: Anti-dsDNA is an SLE marker and does not explain a nucleolar pattern.
Question 3 · Medium
A HEp-2 ANA shows about 10 bright dots in each nucleus, with no dots on the chromosomes of dividing cells. With which disease is this pattern most associated?
1. ALimited systemic sclerosis
2. BSystemic lupus erythematosus
3. CMixed connective tissue disease
4. DPrimary biliary cholangitis
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Answer: D · Primary biliary cholangitis
The multiple nuclear dots pattern (about 6 to 20 dots per nucleus) is caused by antibodies to sp100 or PML proteins and is strongly linked with primary biliary cholangitis, sometimes when antimitochondrial antibody is negative. Centromere staining looks similar but shows many more dots (about 40 to 80), which line up on the chromosomes of dividing cells. The metaphase cells are therefore the key to telling the two patterns apart. Nuclear dots should prompt liver tests and antimitochondrial or sp100 antibody testing.
- A: Limited systemic sclerosis goes with centromere staining: more dots, also seen on the chromosomes.
- B: SLE is linked with homogeneous or speckled patterns, not nuclear dots.
- C: MCTD gives a coarse speckled pattern from anti-U1-RNP.
Question 4 · Hard
A 31-year-old woman with SLE has a deep vein thrombosis. On one sample, anticardiolipin IgG is 62 GPL units and anti-beta-2 glycoprotein I IgG is positive, both above the 99th percentile. To meet the laboratory criteria for antiphospholipid syndrome, the next step is:
1. ATest for lupus anticoagulant while on warfarin
2. BRepeat both tests at least 12 weeks later
3. CRepeat both tests within 1 week
4. DNone; one positive result is enough
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Answer: B · Repeat both tests at least 12 weeks later
Antiphospholipid antibodies can appear briefly after infections or some drugs, so the classification criteria require persistence: the same antibody positive on two or more occasions at least 12 weeks apart. The laboratory criteria are lupus anticoagulant and medium or high levels of anticardiolipin or anti-beta-2 glycoprotein I antibodies. Lupus anticoagulant tests are unreliable during warfarin, heparin or direct oral anticoagulant therapy, while the solid-phase antibody assays are not affected. Confirmed antiphospholipid syndrome usually means longer anticoagulation.
- A: Warfarin prolongs clotting times and makes lupus anticoagulant results unreliable.
- C: One week is too short to separate transient from persistent antibodies.
- D: Transient antibodies are common, so one positive result does not meet the criteria.
Question 5 · Easy
In the 2019 EULAR/ACR classification criteria for SLE, the entry criterion is an ANA, on HEp-2 cells or an equivalent test, at a titer of at least:
1. A1:80
2. B1:40
3. C1:160
4. D1:320
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Answer: A · 1:80
The 2019 EULAR/ACR criteria require a positive ANA of at least 1:80 on HEp-2 cells, or an equivalent positive test, before the other criteria are scored. Weighted clinical and immunologic items, such as anti-dsDNA, anti-Sm, low complement and antiphospholipid antibodies, are then added, and 10 or more points with at least one clinical criterion classifies SLE. A negative ANA therefore makes SLE very unlikely.
- B: 1:40 is below the entry level and is often found in healthy people.
- C: 1:160 is used as a cutoff by some laboratories but is not the criterion level.
- D: 1:320 is higher than the criterion requires.
Question 6 · Medium
A 12-year-old girl has jaundice and ALT 650 U/L (reference < 40 U/L). Viral hepatitis markers, ANA and anti-smooth muscle antibody are negative, and IgG is high. The antibody most likely to be positive is:
1. AAnti-centromere antibody
2. BAnti-LKM-1
3. CAnti-histone antibody
4. DAntimitochondrial antibody
Answer and explanation in LearnFree account
Question 7 · Hard
A 60-year-old with kidney failure has a perinuclear pattern on ethanol-fixed neutrophils in an ANCA IFA. The same serum gives a strong homogeneous ANA on HEp-2 cells at 1:1280. What is the best next step?
1. ATest anti-MPO and anti-PR3 by immunoassay
2. BReport P-ANCA as confirmed vasculitis
3. CReport the result as C-ANCA instead
4. DRepeat the IFA on ethanol-fixed slides
Answer and explanation in LearnFree account
Question 8 · Hard
A 29-year-old woman with SLE, well controlled on hydroxychloroquine, has a fever of 39 °C and a productive cough. Results: ESR 88 mm/h; CRP 160 mg/L (reference < 5); WBC 12.5 x10^9/L, mainly neutrophils; C3 and C4 normal and unchanged; anti-dsDNA unchanged from her last visit. What is the most likely cause of the fever?
1. ABacterial infection
2. BDrug-induced lupus
3. CA lupus flare
4. DLupus nephritis
Answer and explanation in LearnFree account
Question 9 · Hard
A 55-year-old woman has dry eyes, dry mouth and swollen parotid glands. Her ANA by HEp-2 IFA is negative at 1:80, but anti-SSA (Ro60) by immunoassay is strongly positive and repeats positive. How should this be interpreted?
1. AAnti-SSA can be reported only after a positive ANA
2. BAnti-SSA can be missed by HEp-2 IFA; the result is valid
3. CThe ANA must be repeated at 1:20 and found positive
4. DThe immunoassay is false positive because the ANA is negative
Answer and explanation in LearnFree account
Question 10 · Medium
A 64-year-old with macrocytic anemia and a low vitamin B12 has positive gastric parietal cell antibodies. Which test would most specifically support pernicious anemia?
1. ATissue transglutaminase IgA
2. BThyroid peroxidase antibody
3. CIntrinsic factor antibody
4. DParietal cell antibody titer
Answer and explanation in LearnFree account
Question 11 · Hard
A 35-year-old woman with joint pain only has: ANA 1:80 speckled; anti-dsDNA by ELISA 38 IU/mL (positive > 30); Crithidia luciliae IFA negative, with no kinetoplast staining; C3 and C4 normal. What is the best interpretation?
1. ALupus nephritis, shown by the dsDNA antibody
2. BLow-avidity anti-dsDNA of low specificity
3. CActive SLE, confirmed by the ELISA result
4. DAnti-histone antibody from drug-induced lupus
Answer and explanation in LearnFree account
Question 12 · Medium
On HEp-2 cells, an ANA shows coarse speckles across the nucleus, sparing the nucleoli, with no staining of the chromosomes in dividing cells. This pattern most often reflects antibodies to:
1. ASSA (Ro) and SSB (La)
2. BSm and U1-RNP
3. CdsDNA and histones
4. DCentromere proteins
Answer and explanation in LearnFree account
Question 13 · Medium
A well 72-year-old woman with no joint, skin or kidney problems has an ANA of 1:80, speckled, found on a routine panel. ENA and anti-dsDNA antibodies are negative. The best interpretation is:
1. AEarly SLE needing immunosuppressive treatment
2. BDrug-induced lupus until proven otherwise
3. CA false result that must be repeated weekly
4. DA common, usually nonspecific finding at this age
Answer and explanation in LearnFree account
Question 14 · Hard
A 47-year-old woman, diagnosed with diffuse cutaneous systemic sclerosis 6 months ago, is admitted with blood pressure 200/120 mm Hg, headache and a rising creatinine. Anti-centromere and anti-topoisomerase I antibodies are negative. Which antibody is most strongly linked to this complication?
1. AAnti-PM-Scl (exosome)
2. BAnti-RNA polymerase III
3. CAnti-Jo-1 (tRNA synthetase)
4. DAnti-U1 ribonucleoprotein
Answer and explanation in LearnFree account

Autoimmune diseases and ANA patterns

A HEp-2 ANA shows about 10 bright dots in each nucleus, with no dots on the chromosomes of dividing cells. With which disease is this pattern most associated?

A 31-year-old woman with SLE has a deep vein thrombosis. On one sample, anticardiolipin IgG is 62 GPL units and anti-beta-2 glycoprotein I IgG is positive, both above the 99th percentile. To meet the laboratory criteria for antiphospholipid syndrome, the next step is:

In the 2019 EULAR/ACR classification criteria for SLE, the entry criterion is an ANA, on HEp-2 cells or an equivalent test, at a titer of at least:

A 12-year-old girl has jaundice and ALT 650 U/L (reference < 40 U/L). Viral hepatitis markers, ANA and anti-smooth muscle antibody are negative, and IgG is high. The antibody most likely to be positive is:

A 60-year-old with kidney failure has a perinuclear pattern on ethanol-fixed neutrophils in an ANCA IFA. The same serum gives a strong homogeneous ANA on HEp-2 cells at 1:1280. What is the best next step?

A 55-year-old woman has dry eyes, dry mouth and swollen parotid glands. Her ANA by HEp-2 IFA is negative at 1:80, but anti-SSA (Ro60) by immunoassay is strongly positive and repeats positive. How should this be interpreted?

A 64-year-old with macrocytic anemia and a low vitamin B12 has positive gastric parietal cell antibodies. Which test would most specifically support pernicious anemia?

A 35-year-old woman with joint pain only has: ANA 1:80 speckled; anti-dsDNA by ELISA 38 IU/mL (positive > 30); Crithidia luciliae IFA negative, with no kinetoplast staining; C3 and C4 normal. What is the best interpretation?

On HEp-2 cells, an ANA shows coarse speckles across the nucleus, sparing the nucleoli, with no staining of the chromosomes in dividing cells. This pattern most often reflects antibodies to:

A well 72-year-old woman with no joint, skin or kidney problems has an ANA of 1:80, speckled, found on a routine panel. ENA and anti-dsDNA antibodies are negative. The best interpretation is:

A 47-year-old woman, diagnosed with diffuse cutaneous systemic sclerosis 6 months ago, is admitted with blood pressure 200/120 mm Hg, headache and a rising creatinine. Anti-centromere and anti-topoisomerase I antibodies are negative. Which antibody is most strongly linked to this complication?