From the Research
The confirmatory test for Haemophilus influenzae is a one-step multiplex PCR assay, which has been shown to be highly sensitive and specific for detecting H. influenzae in clinical samples, as demonstrated in a 2018 study 1. To perform this test:
- Obtain a sample from the patient (e.g., blood, cerebrospinal fluid, or respiratory secretions)
- Use a one-step multiplex PCR assay to detect the presence of H. influenzae DNA
- The assay should target specific genes, such as ompP6 and bexA, to distinguish between encapsulated and non-typeable H. influenzae
- The sensitivity and specificity of the multiplex PCR assay should be high, with a detection limit of 1.89 × 10^3 copies/μL, as reported in the 2018 study 1 Additionally, culture and identification tests can be used, which involve:
- Obtaining a sample from the patient (e.g., blood, cerebrospinal fluid, or respiratory secretions)
- Culturing the sample on chocolate agar, which contains factors essential for H. influenzae growth
- Incubating the culture at 35-37°C in a CO2-enriched environment for 24-48 hours
- Examining for small, grayish, translucent colonies
- Performing further identification tests, such as X and V factor requirement tests, serotyping (particularly for type b), and MALDI-TOF mass spectrometry However, the one-step multiplex PCR assay is a more rapid and sensitive method for detecting H. influenzae, especially in cases where antibiotic treatment has already begun, as supported by studies such as the 2012 study 2 and the 2003 study 3. Some other studies, such as the 1990 study 4 and the 1998 study 5, also demonstrate the effectiveness of PCR tests for detecting H. influenzae, but the 2018 study 1 provides the most recent and highest-quality evidence for the use of a one-step multiplex PCR assay.