Question
What is germ tube test
Answer
The germ tube test is a rapid, simple presumptive identification test for Candida albicans (and the closely related C. dubliniensis).
Principle: when yeast cells of C. albicans are suspended in serum and incubated at 37°C for 2–3 hours, they produce a characteristic germ tube — a thin filamentous outgrowth lacking a constriction at its point of origin from the parent cell (distinguishing it from a true pseudohypha, which shows a constriction).
Interpretation: presence of germ tubes = positive, presumptively identifying C. albicans/C. dubliniensis; absence = negative, suggesting a non-albicans Candida species requiring further testing for identification.
Clinical significance: rapid, low-cost, widely used first-line presumptive test, directly influencing empirical antifungal therapy decisions while definitive identification/susceptibility testing is pending.