DPS

By spotting and drying plasma drops onto a filter paper card, DPS can be prepared similar to DBS. Rottinghaus et al. compared the performance of DBS and DPS against plasma in HIV VL determination and HIVDRT. Their data showed that DBS, not DPS specimens, rendered VL readouts comparable to plasma, and that DPS had a significantly lower HIVDRT success rate as compared to DBS (38.9% vs. 100%) for specimens with VL ≥1000 copies/mL [46]. The high concordance of VL determination and PCR amplification results between DPS and DNase-treated DBS specimens confirms the proviral DNA contribution to the DBS-based HIVDR data [45]. It also necessitates a shorter storage time, a lower ambient temperature, and a shorter transportation for DPS than DBS due to reduced RNA stability [47].

While DPS consistently produces lower VL values, DPS-derived HIVDR data are highly comparable with those derived from plasma of the same patients [39], implying that the RNA degradation-induced HIV template loss in DPS is non-selective and HIVDR vari-

ants are not affected disproportionally. It makes DPS a better option than DBS for clinical HIVDR monitoring. The trade-off of the additional spotting and drying procedures is the relief of the stringent shipping and storage requirements for the fresh plasma specimens, which could be advantageous in certain circumstances.
