Audu Rosemary A, Okoye Rosemary N, Onwuamah Chika K, Ige Fehintola A, Musa Adesola Z, Odunukwe Nkiruka N, Onwujekwe Daniel I, Ezechi Oliver C, Idigbe Emmanuel O, Kanki Phyllis J
Human Virology Laboratory, Nigerian Institute of Medical Research, Lagos, Nigeria.
Clinical Diagnostic Laboratory, Nigerian Institute of Medical Research, Lagos, Nigeria.
Afr J Lab Med. 2015 Sep 30;4(1):178. doi: 10.4102/ajlm.v4i1.178. eCollection 2015.
In order to scale up access to HIV counselling and testing in Nigeria, an HIV diagnostic algorithm based on rapid testing was adopted. However, there was the need to further evaluate the testing strategy in order to better assess its performance, because of the potential for false positivity.
The objective of this study was to compare positive HIV test results obtained from the approved rapid testing algorithm with results from western blot tests performed on samples from the same patient.
A retrospective review was conducted of HIV screening and confirmatory results for patients seen between 2007 and 2008. Rapid test and western blot results were extracted and compared for concordance. Discordant results were further reviewed using a combination of HIV-1 RNA viral load and CD4+ cell count test results and clinical presentation from medical records.
Analysis of 2228 western blot results showed that 98.3% ( = 2191) were positive for HIV-1, 0.4% ( = 8) were positive for HIV-2 and 0.3% ( = 7) were dual infections (positive for both HIV-1 and HIV-2); 0.6% ( = 13) were indeterminate and 0.4% ( = 9) were negative. Further investigation of the 13 indeterminate results showed nine to be HIV-1 positive and four to be HIV-negative, for a total of 13 negative results. The positive predictive value of the HIV counselling and testing algorithm was 99.4%.
Using the rapid testing algorithm alone, false positives were detected. Therefore, effective measures such as training and retraining of staff should be prioritised in order to minimise false-positive diagnoses and the associated potential for long-term psychological and financial impact on the patients.
为扩大尼日利亚艾滋病病毒咨询与检测的可及性，采用了一种基于快速检测的艾滋病病毒诊断算法。然而，由于存在假阳性的可能性，有必要进一步评估该检测策略，以便更好地评估其性能。
本研究的目的是比较经批准的快速检测算法得出的艾滋病病毒检测阳性结果与对同一患者样本进行的蛋白质印迹法检测结果。
对2007年至2008年期间就诊患者的艾滋病病毒筛查和确证结果进行回顾性分析。提取快速检测和蛋白质印迹法的结果并比较其一致性。使用艾滋病病毒1型RNA病毒载量和CD4+细胞计数检测结果以及病历中的临床表现对不一致的结果进行进一步分析。
对2228份蛋白质印迹法检测结果的分析表明，98.3%（n = 2191）为艾滋病病毒1型阳性，0.4%（n = 8）为艾滋病病毒2型阳性，0.3%（n = 7）为双重感染（艾滋病病毒1型和艾滋病病毒2型均为阳性）；0.6%（n = 13）结果不确定，0.4%（n = 9）为阴性。对13份不确定结果的进一步调查显示，9份为艾滋病病毒1型阳性，4份为艾滋病病毒阴性，共计13份阴性结果。艾滋病病毒咨询与检测算法的阳性预测值为99.4%。
仅使用快速检测算法会检测出假阳性结果。因此，应优先采取有效措施，如对工作人员进行培训和再培训，以尽量减少假阳性诊断以及对患者造成的长期心理和经济影响的相关可能性。
