Fungal 18S rRNA Gene Detection by Quantitative PCR (Serum/Plasma)

What This Test Measures

The test looks for a specific genetic sequence (18S rRNA gene) from fungi in your blood. This sequence is unique to certain types of fungi, including those that can cause serious infections like cryptococcosis or histoplasmosis. The test uses a probe to detect and quantify this genetic material, which helps confirm if fungi are present in your bloodstream.

Why It Might Be Ordered

Your healthcare provider may order this test if you have symptoms of a fungal infection (such as fever, fatigue, or organ dysfunction) and suspect a fungal cause, especially in high-risk groups like immunocompromised patients or those with prolonged hospital stays.

Sample Collection and Processing

A blood sample is drawn from a vein, typically in a clinic or hospital setting. The blood is processed to separate plasma or serum, which is then analyzed for fungal genetic material using a specialized PCR technique. This method is highly sensitive and specific for detecting fungal DNA.

Limitations and Considerations

While this test is highly accurate for detecting fungal DNA, it does not distinguish between live and dead fungal cells. Results may be positive if fungi were present in your body at some point, even if no active infection exists. False positives can occur in rare cases, such as contamination or cross-reactivity with other organisms.