{"doi":"10.1093/ofid/ofac405","title":"Tenofovir-Diphosphate in Dried Blood Spots vs Tenofovir in Urine/Plasma for Oral Preexposure Prophylaxis Adherence Monitoring","abstract":"Abstract Background Tenofovir-diphosphate (TFV-DP) measured in dried blood spots (DBS) and tenofovir (TFV) measured in urine/plasma have been used to measure TFV-based oral pre-exposure prophylaxis (PrEP) adherence. However, there are limited data comparing these 3 metrics and their appropriate use for PrEP adherence monitoring. Methods We collected DBS, urine, and plasma samples from HIV-negative adults randomized to a low (2 doses/week), moderate (4 doses/week), or perfect (7 doses/week) adherence group (via directly observed therapy) of tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) for 6 weeks, followed by a 4-week washout phase. Drug concentrations were measured using liquid chromatography tandem mass spectrometry. Linear mixed-effects modeling was used to examine associations between drug concentrations and dosing time. Results Among 28 participants, the median age was 33 years, and 12 (43%) were female. At steady state, 25th percentile TFV-DP concentrations were 466, 779, and 1375 fmol/3 mm punch in the low, moderate, and perfect adherence group, respectively. Correlation was stronger between quantifiable TFV-DP and plasma TFV (r = 0.65; P < .01) than between TFV-DP and urine TFV (r = 0.50; P < .01). Among all participants, each additional week of cumulative dosing on average led to a mean increase of 158 fmol/3 mm punch (P < .001) in TFV-DP during the dosing phase. Each additional day after the last dose was associated with 43 fmol/3 mm punch lower TFV-DP (P = .07). Conclusions TFV-DP levels in DBS provide valuable insight into both dosing recency and cumulative doses from variable adherence patterns. Our observed benchmark TFV-DP concentrations were slightly higher than prior predicted estimates based on convenience samples.","journal":"Open Forum Infectious Diseases","year":2022,"id":264403,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":12,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.8952,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2022-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":765983,"name":"Rachel W. Kubiak","orcid":"0000-0002-2315-4112","position":1,"is_corresponding":false},{"id":922440,"name":"Oraphan Siriprakaisil","orcid":null,"position":2,"is_corresponding":false},{"id":922441,"name":"Virat Klinbuyaem","orcid":null,"position":3,"is_corresponding":false},{"id":922442,"name":"Pra ornsuda Sukrakanchana","orcid":null,"position":4,"is_corresponding":false},{"id":922014,"name":"Ratchada Cressey","orcid":"0000-0003-4346-4422","position":5,"is_corresponding":false},{"id":451361,"name":"Hideaki Okochi","orcid":"0000-0002-8519-7409","position":6,"is_corresponding":false},{"id":241509,"name":"Monica Gandhi","orcid":"0000-0002-7025-1994","position":7,"is_corresponding":false},{"id":354236,"name":"Tim R. Cressey","orcid":"0000-0002-8106-0974","position":8,"is_corresponding":false},{"id":490093,"name":"Paul K. Drain","orcid":"0000-0002-9569-4097","position":9,"is_corresponding":false},{"id":764345,"name":"Xin Niu","orcid":"0000-0002-9136-3434","position":0,"is_corresponding":true}],"reference_count":31,"raw_metadata":null,"created_at":"2026-07-19T00:26:37.567338Z","pmid":"36004315","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}