Giardiasis in North West England: faecal specimen requesting rates by GP practice

Area of Science:

• Public Health
• Infectious Disease Epidemiology
• General Practice

Background:

• Undiagnosed giardiasis is a concern in the UK.
• Diagnosis often depends on general practitioners (GPs) requesting laboratory specimens.
• Variations in GP testing practices may influence reported disease incidence.

Purpose of the Study:

• To assess specimen request rates per GP practice in Central Lancashire.
• To examine inter-practice differences in testing.
• To investigate spatial variation in specimen rates, adjusting for deprivation.

Main Methods:

• Binomial and Poisson regression models with random effects for GP practice were fitted.
• Analysis focused on specimen request rates, positive test proportions, and cumulative positive specimen rates.
• Spatial correlation of specimen rates was assessed over single and multiple years.

Main Results:

• Significant differences in specimen request rates were observed between GP practices (P < 0.001).
• No significant differences were found in the proportion of positive tests or positive specimens per population.
• A significant difference in the cumulative rate of positive specimens per practice population over 9 years was noted (P < 0.001).
• Neither annual nor cumulative specimen rates showed significant spatial correlation.

Conclusions:

• GP practices exhibit variability in requesting diagnostic specimens for suspected giardiasis.
• The spatial distribution of giardiasis incidence is unlikely to be influenced by variations in GP specimen request rates.
• Further research into diagnostic delays and patient-level factors may be warranted.