Family Screening Letter

Dear Doctor,

• 1st degree relatives have a 10% or greater chance of also being affected by coeliac disease.
• Typical symptoms include gastrointestinal upset, lethargy or anaemia, but symptoms often go unrecognised, or the patient may be truly asymptomatic.
• Early diagnosis and treatment of coeliac disease is important to reduce morbidity such as osteoporosis, malignancy, subfertility and general malaise.
• Targeted screening is the most effective way to detect coeliac disease.

How to test:

1. Confirm your patient is consuming a gluten-containing diet for accurate results (see over page for management if they are following a gluten free diet).
2. Request the following blood tests:
   • Coeliac serology, specifically:
   1. Transglutaminase-IgA (tTG-IgA)
   2. Deamidated gliadin peptide-IgG (DGP-IgG)
   • HLA-DQ2/8 genotyping (also known as Coeliac disease HLA typing, useful when screening high-risk individuals e.g. those with a positive family history)

How to interpret:

• If tTG-IgA and/or DGP-IgG is positive refer to a gastroenterologist for confirmatory small bowel biopsy. Serology alone is insufficient to diagnose coeliac disease.
• A positive HLA-DQ2/8 gene test is not diagnostic of coeliac disease in isolation (approximately half of the general population are positive).
• A negative HLA-DQ2/8 gene test has strong negative predictive value (<1% likelihood of coeliac disease being present) and means coeliac disease can be excluded.
• If coeliac serology is negative but the patient is symptomatic and positive for HLA-DQ2 and/or HLA-DQ8 then consider referral to a gastroenterologist for further work-up.
• A HLA-DQ2 and/or HLA-DQ8 positive relative with normal coeliac serology is at-risk for the future development of coeliac disease and follow-up is warranted. Repeat screening is recommended if they become symptomatic (suggestive symptoms indicated over the page).

Thank you for your care.

Yours sincerely,