Govender Kerusha, Parboosing Raveen, Siyaca Ntombizandile, Moodley Pravikrishnen
Department of Virology, Inkosi Albert Luthuli Central Hospital, National Health Laboratory Service, Durban, KwaZulu-Natal, South Africa.
Department of Virology, School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, South Africa.
Afr J Lab Med. 2016 Feb 25;5(1):349. doi: 10.4102/ajlm.v5i1.349. eCollection 2016.
Poor quality dried blood spot (DBS) specimens are usually rejected by virology laboratories, affecting early infant diagnosis of HIV. The practice of combining two incompletely-filled DBS in one specimen preparation tube during pre-analytical specimen processing (i.e., the two-spot method) has been implemented to reduce the number of specimens being rejected for insufficient volume.
This study analysed laboratory data to describe the quality of DBS specimens and the use of the two-spot method over a one-year period, then validated the two-spot method against the standard (one-spot) method.
Data on HIV-1 PCR test requests submitted in 2014 to the Department of Virology at Inkosi Albert Luthuli Central Hospital in KwaZulu-Natal province, South Africa were analysed to describe reasons for specimen rejection, as well as results of the two-spot method. The accuracy, lower limit of detection and precision of the two-spot method were assessed.
Of the 88 481 specimens received, 3.7% were rejected for pre-analytical problems. Of those, 48.9% were rejected as a result of insufficient specimen volume. Two health facilities had significantly more specimen rejections than other facilities. The two-spot method prevented 10 504 specimen rejections. The Pearson correlation coefficient comparing the standard to the two-spot method was 0.997.
The two-spot method was comparable with the standard method of pre-analytical specimen processing. Two health facilities were identified for targeted retraining on specimen quality. The two-spot method of DBS specimen processing can be used as an adjunct to retraining, to reduce the number of specimens rejected and improve linkage to care.
质量不佳的干血斑（DBS）标本通常会被病毒学实验室拒收，这影响了婴儿早期HIV诊断。在分析前标本处理过程中，将两个未装满的DBS合并到一个标本制备管中（即两点法）的做法已被采用，以减少因体积不足而被拒收的标本数量。
本研究分析实验室数据，以描述DBS标本的质量以及一年期间两点法的使用情况，然后将两点法与标准（单点）法进行验证。
分析2014年提交给南非夸祖鲁-纳塔尔省因科西·阿尔伯特·卢图利中心医院病毒学部门的HIV-1 PCR检测请求数据，以描述标本拒收原因以及两点法的结果。评估两点法的准确性、检测下限和精密度。
在收到的88481份标本中，3.7%因分析前问题被拒收。其中，48.9%因标本体积不足被拒收。两家医疗机构的标本拒收率明显高于其他机构。两点法避免了10504份标本被拒收。将标准法与两点法进行比较的Pearson相关系数为0.997。
两点法与分析前标本处理的标准方法相当。确定了两家医疗机构进行标本质量的针对性再培训。DBS标本处理的两点法可作为再培训的辅助手段，以减少被拒收的标本数量并改善护理联系。
