Abstract:

【Abstract】 Objective  To assess the quality of microscopy-based malaria diagnosis in Yunnan Province from August 2012 to October 2014, and analyze the relevant factors.  Methods  Blood samples were collected from patients diagnosed as malaria by microscopy in county-level laboratories of Yunnan Province. The blood smears and blood filter paper samples were prepared and submitted to the provincial malaria diagnosis reference laboratory for further confirmation by both microscopy and the genetic approach. Coincidence rates for species identification between county and provincial laboratories were analyzed using the SPSS 21.0 software.  Results  From August 2012 to October 2014, 1 400 malaria cases were diagnosed with microscopy in 72 counties of Yunnan Province. Among them, the cases of falciparum malaria, vivax malaria, and unclassified malaria accounted for 18.4%(252/1 400), 79.3%(1 105/1 400) and 3.1% (43/1 400), respectively. The percentage of unclassified malaria cases reached a peak in 2012(3.5%， 9/257). The coincidence rate for species identification with microscopy between county-level and provincial-level laboratories was 70.1%(845/1 216) in 2012， being the lowest during 2012-2014, and the coincidence rate for diagnosis of positive infection was 77.6% (943/1 216). Similarly, the coincidence rates for species identification and for positive infection between county-level laboratories using microscopy and the provincial-level laboratory using the genetic approach were 81.3%(150/185) and 85.0% (157/185) respectively in 2012, being also the lowest during 2012-2014. In the provincial laboratory, the inconsistency rate for species identification between microscopy and the genetic approach was 8.7% (97/1 120), predominately the infection-negative results by microscopy versus falciparum malaria， vivax malaria or mixed infection revealed by the genetic approach (57.7%， 56/97). The sampling coverage rate in counties was the lowest in November 2012 (46.9%, 82/175). The blood smear preparation scored 69.8, 70.4 and 78.8 (P<0.05) in 2012, 2013 and 2014, respectively.  Conclusion  The quality of laboratory malaria diagnosis has been significantly improved in most counties of Yunnan Province since 2013.

Key words: Yunnan, Malaria, Laboratory, Diagnosis, Quality