**Question:** Diagnosis of Filariasis is confirmed most commonly done by

A. Microscopy
B. Serology
C. Molecular techniques
D. Clinical examination

**Correct Answer:** C. Molecular techniques

**Core Concept:** Filariasis is a mosquito-borne parasitic disease caused by the infection with filarial worms, primarily Wuchereria bancrofti, Brugia malayi, and Brugia timori. The disease affects the lymphatic system, leading to Lymphatic Filariasis (LF). Diagnosis plays a crucial role in managing the disease, and there are multiple methods available.

**Why the Correct Answer is Right:** Molecular techniques, particularly the Polymerase Chain Reaction (PCR), are widely accepted as the gold standard for diagnosing filariasis. PCR can detect the presence of filarial DNA in the patient's blood, which is not visible in microscopy, serology, or clinical examination alone. These methods are either less sensitive or specific in detecting filarial infection.

**Why Each Wrong Option is Incorrect:**

A. Microscopy: Although microscopy can detect microfilariae (immature worms) in the blood, it is not always reliable, as the infection may be subpatent or patent but without microfilaraemia.
B. Serology: Serological tests detect antibodies produced in response to the infection, but they may not always correlate with the actual infection status due to false positive or false negative results.
D. Clinical examination: Clinical examination relies on the identification of clinical manifestations, which can be nonspecific and overlap with other conditions.

**Clinical Pearl:** In endemic areas, a combination of methods like microscopy, serology, and molecular techniques is often used for accurate filariasis diagnosis. However, considering the limitations of individual methods, molecular techniques (PCR) are the most reliable method for filariasis diagnosis.