The percentages of participants in clinical studies haven't always been perfectly representative of a particular group.

This research examines the variables that affect a patient's choice to enroll in, discontinue participation in, or resume participation in a clinical trial for hairy cell leukemia.

It will also try to analyze data from the perspective of different demographic groups to check for recurring trends which might yield insights for the sake of hairy cell leukemia studies.

Inclusion Criteria:

• Aged ≥ 18 years old
• Ability to understand and the willingness to sign a written informed consent document.
• Willing and able to comply with scheduled visits, treatment schedule, laboratory tests and other requirements of the study.

Exclusion Criteria:

• Is pregnant, breastfeeding or expecting to conceive within the projected duration of the study
• Any mental or medical condition that prevents the patient from giving informed consent or participating in the trial
• Patients with any significant history of non-compliance to medical regimens or with inability to grant a reliable informed consent.

Patients who are actively considering involvement in an observational hairy cell leukemia clinical trial, but have not yet completed enrollment and registration.