**Core Concept**
Epidemiological methods of population survey are crucial in understanding disease patterns and distribution. These methods help in identifying risk factors, prevalence, and incidence of diseases. The four main epidemiological methods are case-control studies, cross-sectional studies, cohort studies, and ecological studies.

**Why the Correct Answer is Right**
To determine which option is not an epidemiological method of population survey, we need to understand the characteristics of each method. Case-control studies involve comparing individuals with a specific outcome (cases) with those without the outcome (controls) to identify potential risk factors. Cross-sectional studies assess the prevalence of a disease or condition in a population at a specific point in time. Cohort studies follow a group of individuals over time to examine the development of a disease or condition. Ecological studies analyze the relationship between exposure and outcome at the population level, rather than the individual level.

**Why Each Wrong Option is Incorrect**
**Option A:** is actually a type of ecological study, which is an epidemiological method. Therefore, it is not the correct answer.
**Option B:** and **Option D:** are also types of epidemiological methods. Case-control studies and cohort studies are both used to investigate the relationship between exposure and outcome.
**Option C:** is not an epidemiological method of population survey. It is actually a type of laboratory test used to diagnose or confirm the presence of a disease.

**Clinical Pearl / High-Yield Fact**
Remember, epidemiological methods are crucial in understanding disease patterns and distribution. The choice of method depends on the research question, study design, and available resources.

**Correct Answer:** C.