Assessment of viable bacteria and bacterial DNA in blood and bloodstain specimens stored under various conditions

Pathogen Detection Using Metagenomic Next-Generation Sequencing of Plasma Samples from Patients with Sepsis in Uganda

“…The sensitivity of mNGS compared to targeted qPCR was low, at 30% overall, and even lower for bacteria at 5%. This was not surprising to us and can likely explained by several factors, including the read depth, limited sample volume, age of the samples (10+ years), different sample types (sequencing on plasma versus qPCR on whole blood), stringency of the background filtering thresholds used, and the potential presence of inhibitory substances to sequencing in human plasma, which have all been previously described ( 21 – 23 ). Several studies have shown similarly variable sensitivity and specificity of mNGS versus PCR ( 24 – 27 ).…”

Etiology of Sepsis in Uganda Using a Quantitative Polymerase Chain Reaction-based TaqMan Array Card

“…Another factor was that these blood samples were stored ~7 years prior to testing; thus, specimen degradation could have occurred. However, it has been shown that DNA in blood samples frozen at −80 o C for 16 months was preserved well [23].…”