Answer:
Health screenings are basically procedures that allow medical professionals to assess the health status of a patient, diagnose different conditions and establish appropriate treatments for patients. Depending on the condition that is being screened for, different screening tests will be administered that will confirm the clinical observations of the healthcare professional and therefore, the diagnosis. As such, the correct pairings here would be:
1. COPD (Chronic obstructive pulmonary disease): X-ray. The reason for this being the correct pairing is that X-rays will allow a physician to observe the appearance of the lungs and diagnose if this condition is present or not.
2. Iron deficiency: Blood cell count. Blood cell formation depends on the availability of iron. When iron is deficient, the bone marrow will not be able to produce enough erythrocytes, and the ones that are, will be unstable and weak. Iron deficiency will be then diagnosed and confirmed by what appears on a blood test, with blood cell count as one of the parameters.
3. Obesity: BMI. BMI is the most common test to know if a person is obese or not. However, many professionals are now also choosing waist measurements as they have discovered the weaknesses in using BMI alone.