CHINESE JOURNAL OF PARASITOLOGY AND PARASITIC DISEASES ›› 2021, Vol. 39 ›› Issue (3): 337-342.doi: 10.12140/j.issn.1000-7423.2021.03.007

• ORIGINAL ARTICLES • Previous Articles     Next Articles

Analysis of malaria detection capability of laboratories in the districts of Shanghai during 2017—2019

ZHANG Yao-guang(), JIANG Li*(), WANG Zhen-yu, ZHU Min, ZHU Qian, MA Xiao-jiang, WU Huan-yu   

  1. Shanghai Municipal Center for Disease Control and Prevention, Shanghai 200336,China
  • Received:2020-08-06 Revised:2020-10-28 Online:2021-06-30 Published:2021-07-05
  • Contact: JIANG Li E-mail:zhangyaoguang@scdc.sh.cn;jiangli@scdc.sh.cn
  • Supported by:
    Science and Technology Innovation Action Plan of Shanghai(20DZ2200300);Research and Technology Development Project of Baise City(20202501)

Abstract:

Objective To recheck the blood samples of malaria cases sent by district-level centers for disease control and prevention (CDC), in Shanghai Municipal Center for Disease Control and Prevention (SCDC), and analyze the review results, in order to provide a basis for improving the malaria diagnostic capability of district CDCs.Methods Blood smears and whole blood samples submitted by the district CDC malaria laboratories were rechecked by SCDC using microscopic examination and nuclear acid detection (nested PCR) during 2017—2019. Using the examination by SCDC as the standard, the positive and negative coincidence rates of microscopic examination, and the sensitivity and specificity of malaria nucleic acid detection performed in district CDC malaria laboratories were analyzed. In 2019, blind assessment of malaria nucleic acid tests was conducted for all district CDCs of each district.Results A total of 232 malaria samples were submitted by district CDCs for rechecking in 2017—2019, among them 225 were complete samples (containing both blood smear and whole blood samples), with a completeness rate of 99.1% (225/227). Of the 225 complete samples, 99 samples were from Jinshan District (44.0%); 35 from Jing’an District (15.6%); 17 from Pudong New District (7.6%); 15 from Hongkou District (6.7%); Qingpu District and Chongming District submitted the least numbers of samples (0 and 1, respectively); while other districts provided less than 6.0% of the samples. The recheck of 225 complete samples showed an overall coincidence rate, positive coincidence rate and negative coincidence rate being 96.0% (216/225), 98.8% (170/172) and 86.8% (46/53), respectively, and the coincidence rate of nucleic acid detection 88.8% (103/116). The district CDCs used the quantitative real-time PCR (qPCR) method for nucleic acid detection, resulting in a sensitivity of 76.6% (85/111), which was significantly different from that of the nested PCR method used by SCDC (87.4%, 97/111) (P < 0.05). The specificity of the two nucleic acid detection methods was 100.0%. Comprehensive evaluation of the 225 samples by using the two detection methods showed that the coincidence rate of district CDCs was 96.9% (218/225), and the misjudgment rate was 3.1% (7/225), including 5 with qualitative errors and 2 with errors in species identification. In 2019, the overall correct detection rate of blind assessment of malaria nucleic acid by district CDCs was 97.5% (78/80). Specifically, the correct detection rate of P. falciparum sample was 94.1% (32/34), which was not significantly different from those of the other four types of samples (P. vivax, P.ovale, P. malariae and negative infection) (P > 0.05). Conclusion From 2017 to 2019, the malaria laboratories of district CDCs showed a strong capability of malaria microscopic examination, but the sensitivity of nuclear acid detection needs to be improved.

Key words: Malaria, Laboratory, Microscopic examination, Nucleic acid detection, Coincidence rate

CLC Number: