Health Screening: Definition, Importance and Principles

Health Screening

• Health screening is preventive care for different age groups.
• The lecture objectives include defining health screening, explaining its importance, aims, and tools, and explaining how screening test performance is measured.
• Further objectives include identifying health screening recommendations for different age groups, discussing ethical considerations, and barriers to health screening.

Definition and Importance

• Health screening is a medical test or procedure performed on members of an asymptomatic population or subgroup to assess the likelihood of having a particular disease.
• Early detection leads to the prevention of disease, disability, and death.
• Early intervention leads to reduced risk of severe complications.
• Autonomy allows individuals to monitor and track their health status.
• Health beliefs influence lifestyle changes and health behaviour.
• Protection prevents unnecessary precautions.

Principles of Screening

• Wilson & Jungner created 10 principles to assess the appropriateness of screening.
• The condition screened for should be an important health problem.
• Accepted treatments should be available for patients with the disease.
• Facilities for diagnosis and treatment should be available.
• There should be a recognizable latent or early symptomatic phase.
• There should be a suitable test or examination.
• The test should be acceptable to the population.
• The natural history of the condition should be understood.
• There should be an agreed policy on whom to treat as patients.
• The cost of case-finding should be economically balanced with possible expenditure on medical care.
• Case-finding should be a continuous process.

Aims of Screening

• Opportunistic screening is part of a clinical encounter for an unrelated illness.
• Mass screening applies to populations or major demographic groups.
• Targeted screening is aimed at smaller groups with specific characteristics associated with high risk of disease.
• Multiphasic screening uses a battery of tests for early detection of preventable diseases.
• Surveillance is a systematic process of gathering and analysing data about specific health problems.

Screening Pathway

• Core steps of a screening pathway include identifying the eligible population, invitation & information, testing, referrals for positives/ reporting for negatives, diagnosis, and intervention/ treatment/ follow-up.

Screening Test Performance

• An ideal screening test would distinguish those with the condition from those without flawlessly, but there is overlap.
• Sensitivity reflects the ability to correctly identify those with the condition as positive.
• Specificity reflects the ability to correctly identify those without the condition as negative.
• A threshold value is chosen as the cut-off between positive and negative test results.
• Changing the threshold value can alter the sensitivity and specificity of a screening test.
• Sensitivity and specificity are fixed properties of a test.
• Screening programs often use highly sensitive screening tests to minimize false negatives, but this increases false positives.
• Positive results need confirmation with a test that has high specificity to exclude false positives.
• Screening programs may include several tests and follow-up investigations.

Tools of Health Screening

• Blood/tissue tests: measure glucose, cholesterol, STDs, genetic markers, biopsies.
• Physical exams: include neurological, rectal, genital, blood pressure, BMI.
• Imaging: include X-rays, ultrasound, MRI, CT scans.
• Questionnaires: used for mental health, substance misuse.

Optimizing Screening Practices

• Clearly defined recommendations are needed for health screening to determine health practice standards and improve public health.
• Standardizing screening practices is achieved through clear guidelines and recommendations.
• National guidelines dictate optimal screening age, intervals, and recommended tests for various population groups.
• A personalized approach uses age and risk factors specific to the healthcare conditions.
• Guidelines can vary between geographical areas, tailored to local health resources and priorities.
• Screening practices should be tailored to support various age groups.
• Target populations include infants and children, adolescents, and adults.

Screening across Age Groups

• Childhood screening protocols focus on developmental milestones, immunizations, genetic disorders, and hearing/vision tests.
• Childhood immunizations help prevent infectious diseases and protect public health through herd immunity.
• Developmental milestones monitor physical, language, and social skills, to facilitate the intervention of optimal growth.
• Routine screening for genetic disorders lead to early detection and intervention, such as sickle cell disease and cystic fibrosis.
• Adolescent health screenings focus on mental health, substance use, and sexual health.
• Mental health screenings are done in schools, health clinics, or community programs using questionnaires, interviews, and observations.
• Substance use assessments identify risky behaviours and enable education and intervention regarding alcohol, drugs, and tobacco.
• Sexual health screenings empower adolescents with knowledge of sexual health and STIs, reducing stigma and enabling informed decisions.
• Adult screenings focus on mitigating chronic disease risks, detecting cancer, and assessing mental health, sexual health, substance misuse, and osteoporosis.
• Screening depends on individual risk and conditions.

Screening Recommendations

• Adults should be screened for hypertension every 1-2 years with a blood pressure check.
• Adults should be screened annually for obesity via Body Mass Index.
• Adults (35-70, if overweight) should be screened for diabetes every 3 years with a fasting glucose and HbA1C test.
• Adults 50-75 should be screened for colorectal cancer every 10 years via colonoscopy or annually with the Fecal Immunochemical Test (FIT).
• Women 40-74 should undergo mammograms for breast cancer every 2 years.
• Cervical cancer screening for women 21-65 via Pap smear/HPV test done every 3 years (Pap) or 5 years (Pap + HPV test).
• Sexually active adults should be annually screened for STIs, and high-risk subgroups should use blood and genital swabs.

Ethical Concerns

• Individuals have to balance individual rights and possible risks while screening.
• Informed consent, beneficence and non-maleficence, confidentiality, and equity and justice are all key ethical concerns that may arise.
• Individuals must decide whether or not to participate in a screening program.
• Screening should do more good than harm by aiming at the accuracy of positives and negatives.
• Data collected from screening should be protected, and access only granted by the individual.
• Disparities based on socioeconomic or demographic backgrounds should be prevented for fair access to screening.

Barriers to Screening

• Socioeconomic barriers include lack of finances and education.
• Access barriers may include remote locations, quality of care and shortage of healthcare providers.
• Psychological barriers are triggered by fear and anxiety as well as resistance.
• Cultural barriers are triggered by cultural health beliefs, and cultural stigma.
• Healthcare policies are impacted by inadequate policies and lack of funding.

Summary

• Early detection prevents disease complications leading to negative health outcomes.
• Challenges of accessing health services include geography, socioeconomic status, knowledge of health services and screening.
• Promotion of health practices via mass media, pamphlets, distribution in communities and counselling during health visits.
• Lifelong monitoring through education, accessibility, and promotion helps early detection and prevention of disease.