The highs and lows of opportunistic Chlamydia testing: uptake and detection in Waikato, New Zealand

The uptake rate of Chlamydia trachomatis (Chlamydia) testing among young New Zealanders is unknown. The aim was to ascertain age-group Chlamydia testing and detection rates within the Waikato area.

A retrospective study was undertaken of all Chlamydia tests within Waikato District Health Board during February to October 2008. Non-genital samples and duplicates for any individual were excluded. New Zealand 2006 census population data served as denominator data.

There were 21 104 Chlamydia tests carried out on Waikato residents during February to October 2008; of these, 10 847 (51.4%) tests were from 15-24-year-olds, and 82.3% were female. Based on tests, uptake among 15-24-year-olds was 22.2%, 36.9% among females and 7.7% among males, compared with 9.3% among 25-44-year-olds. Based on individuals, uptake among 15-24-year-olds was 17.4%: 28.4% for females and 6.7% for males, with similar rates for Māori (13.5%) and non-Māori (15%). Overall 15.8% of tests from 15-24-year-olds were positive, 14.4% in females and 23.0% in males (p<0.001), with positivity double among Māori (24.2% vs 12.5%; p<0.001).

High rates of Chlamydia testing and uptake, particularly among local 15-24-year-old women, may explain the high Chlamydia surveillance rates in the Waikato district. While a high testing rate among young women is encouraging, lower testing among men is notable. This better understanding of existing Waikato testing and detection patterns helps prioritise local efforts during planned implementation of Chlamydia primary care guidelines, particularly around targeting testing, optimising case management and emphasising effective partner notification.