The PICADAR calculator helps estimate the likelihood of Primary Ciliary Dyskinesia (PCD) by evaluating a patient's symptoms through eight targeted questions. Each response translates into a numerical score based on a specific scoring framework, which together reflect the risk of PCD.

Patients answer the following questions:

- Do they have a daily wet cough that started in early childhood? A "Yes" translates to 0 points, whereas "No" scores 15 points.
- Were they born preterm or at full term? Being born "Term" adds 2 points.
- Did they experience chest symptoms such as tachypnea, cough, or pneumonia in the neonatal period? If "Yes," 2 points are awarded.
- Were they admitted to a neonatal unit? Similar to chest symptoms, a "Yes" yields 2 points.
- Do they have a situs abnormality like situs inversus or heterotaxy? A "Yes" response results in 4 points.
- Is there a congenital heart defect present? This also contributes 2 points if responded with "Yes."
- Do they have persistent perennial rhinitis? A "Yes" equals 1 point.
- Finally, do they experience chronic ear or hearing symptoms such as glue ear, serous otitis media, hearing loss, or ear perforation? A "Yes" scores another point.

Responses are converted into scores, and all are summed to create a total. This sum determines the risk of PCD based on the following score-to-risk mapping:

- Score of 0 corresponds to a 0.1% risk.
- Score of 1 indicates a 0.3% risk.
- Score of 2 suggests 0.8% risk.
- Score of 3 means 1.9% risk.
- Score of 4 estimates a 4.7% risk.
- Score of 5 reaches an 11.1% risk.
- Score of 6 suggests 23.9% risk.
- Score of 7 indicates a 44.1% risk.
- Score of 8 corresponds to a 66.4% risk.
- Score of 9 represents 83.3% risk.
- Score of 10 implies 92.6% risk.
- Score of 11 shows 96.9% risk.
- Score of 12 corresponds to 98.7% risk.
- A score of 13 or higher suggests an overwhelming 99.8% risk of PCD.

Crucially, a score of -1 or below reflects a scenario not supported by this calculator, emphasizing its reliance on the presence of a wet cough as a key factor.

The Primary Ciliary Dyskinesia Rule, also known as PICADAR, is a clinical calculator used in the diagnosis of Primary Ciliary Dyskinesia (PCD), a rare, genetically heterogeneous disorder characterized by chronic upper and lower respiratory tract disease. This calculator is applicable to patients who present with symptoms suggestive of PCD, such as chronic cough, chronic rhinosinusitis, and recurrent or persistent lower respiratory tract infections.

The PICADAR score is a useful tool for identifying patients who are at high risk of having PCD and who may benefit from further diagnostic testing. It uses seven clinical features to calculate a score, including full-term gestation, persistent wet cough, persistent rhinitis, neonatal chest symptoms, situs inversus or unexplained cardiac defects, congenital hearing defect, and a history of PCD in a sibling.

Exclusion criteria for the use of the PICADAR score may include patients who have other known causes for their respiratory symptoms, such as cystic fibrosis, asthma, or immunodeficiency disorders. It's also important to note that while the PICADAR score can help identify patients at high risk for PCD, it is not definitive and further diagnostic testing is required for a confirmed diagnosis.

Primary ciliary dyskinesia rule (PICADAR)