Sputum smear microscopy referral rates and turnaround time in the Tonga Islands

The National Tuberculosis Programme and the National Reference Laboratory, located on the main island of Tonga, Tongatapu, and three district hospital laboratories located on the outer islands.

To compare Tongatapu with Tonga's outer islands with respect to sputum referral rates, numbers of samples per patient, sample quality, test results and time from sending sample to obtaining results and from obtaining results to treatment initiation.

Retrospective study involving record review of laboratory and TB treatment registers in Tonga's four hospitals from 2003 to 2012.

Of 3078 sputum samples submitted, 71.7% were of good quality. Sputum referral rates on Tongatupu were nearly twice as high as those on the outer islands (353 vs. 180 per 100 000 population). The mean smear turnaround times on Tongatapu and the outer islands were respectively 4.02 and 4.11 days. Of 83 positive cases, 91.2% were treated within a day in Tongatapu compared with 80% in the outer islands.

Referral rates for sputum smear testing differed in the main and the outer islands in Tonga, but turnaround times did not. Records of sputum quality and dates had limitations, necessitating interventions with TB-specific laboratory guidelines and registers. Further research is required to understand the differences in referral rates.