Capillary Sampling in Clinical Populations Undergoing Monitoring

Capillary Sampling in Clinical Populations Undergoing Monitoring

Many people with long-term health conditions require regular blood tests to monitor their disease or medications. These blood tests are usually performed by taking blood from a vein during a hospital or clinic appointment. This can be inconvenient, time-consuming and difficult for some people, particularly those who live far from hospital, have reduced mobility, require frequent tests, or experience anxiety about attending healthcare settings or having blood taken.

Capillary blood sampling devices allow people to collect a small blood sample themselves, usually from the upper arm or fingertip, which can then be sent to a laboratory by post. These devices have shown promising results for some blood tests, but there is insufficient evidence of which tests remain accurate when samples are collected at home, posted to the laboratory and subjected to postage conditions and delayed analysis.

The CAPSICUM study will compare blood samples collected using patient-operated capillary sampling devices with routine venous blood samples already being taken as part of participants' usual clinical care. We will investigate whether a wide range of blood tests produce similar results using both methods and assess how delayed analysis, postal transport and home collection affect test accuracy.

Participants will attend only one study visit, which will take place during a routine clinic appointment. Some participants will also be invited to collect an additional blood sample at home and return it by post, and to complete a brief questionnaire about their experience.

The findings from this study will help identify which blood tests can be safely monitored using home capillary blood sampling. This could improve access to blood monitoring, reduce unnecessary hospital visits, make monitoring more convenient for patients, and support the development of safe, evidence-based remote monitoring pathways within the NHS.

Inclusion Criteria:

Eligible participants are individuals who require routine venous blood sampling as part of their usual clinical care and who represent clinical populations in which remote capillary blood sampling may improve access to monitoring or patient experience.

All participants must:

• Be attending a routine clinical appointment during which venous blood sampling is planned as part of standard clinical care for disease monitoring or therapeutic drug monitoring.
• Be willing and able to undertake capillary blood sampling independently or with appropriate assistance.

Adult participants must:

• Be aged ≥18 years of age.
• Have capacity to provide written informed consent.

Paediatric participants must:

• Be aged 6-15 years of age.
• If aged 6-11, be attending with a parent or legal guardian able to provide written informed consent and provide age-appropriate assent where applicable.
• If aged 12-15: be attending with a parent or legal guardian able to provide written informed consent and provide age-appropriate assent where applicable OR if deemed to have capacity themselves, be able to provide written informed consent and be attending with a parent or legal guardian who agrees to their participation.

Additional eligibility criteria

Autoimmune disease group: participants must have a diagnosis of immune-mediated disease based on the assessment of their treating clinician.

Transplant recipient group: participants must be the recipient of a functioning kidney, kidney-pancreas, or islet transplant.

Mental health group: participants must have a diagnosis of a mental health disorder based on the assessment of their treating clinician.

Paediatric group: participants must be attending a paediatric clinic and require blood sampling as part of standard clinical care.

Exclusion Criteria:

• Inability or unwillingness to provide informed consent, or, for paediatric participants, absence of parental or legal guardian consent or age-appropriate assent where applicable.
• Skin disease, infection, injury, or other local factors at the intended sampling site that would make capillary blood collection unsafe or impractical.
• Known allergy or hypersensitivity to any materials used in the capillary blood sampling devices.
• Inability to undertake the capillary sampling procedures independently or with appropriate assistance.