The STABLE Program Practice Exam

In the context of transillumination of the chest, false positives can occur if there are conditions that hinder the accurate assessment of light passing through the chest wall. When considering the specific choice of chest wall edema (hydrops), this condition can lead to a false positive result due to the presence of excess fluid in the tissues, which affects how light is transmitted.

The presence of edema can scatter the light or create a misleading appearance that suggests the presence of a mass or pathology when none exists. This is because the fluid can create a layer that alters the expected transillumination pattern, causing misinterpretation during the examination.

While thickness of the chest wall, darkly pigmented skin, and non-perpendicular light sources can influence transillumination readings, each of these factors does not directly result in false positives in quite the same manner as edema does. Chest wall thickness can affect how much light penetrates but doesn't actively create a misleading brightness that mimics pathology. Similarly, darkly pigmented skin can reduce the amount of light seen but doesn’t inherently lead to a diagnosis of a condition. Non-perpendicular light sources can diminish clarity but would not specifically alter the interpretation to appear as a false positive for a pathological condition.

Thus, chest wall edema