Jannetto, Paul J.

Background: Itraconazole is the preferred antifungal agent for mild to moderate histoplasmosis and step-down therapy following amphotericin B treatment. Although hydroxy-itraconazole, a major metabolite of itraconazole, displays antifungal activity comparable with that of the parent compound, its role in therapeutic drug monitoring targets for histoplasmosis remains uncertain. Methods: The objective was to compare clinical outcomes and adverse events using itraconazole parent-compound concentrations alone versus combined itraconazole and hydroxy-itraconazole concentrations in patients treated for histoplasmosis. This retrospective cohort study included adults with probable or proven histoplasmosis who received itraconazole and had at least 1 documented serum concentration. The primary outcome was clinical response across 3 groups: (1) parent (itraconazole parent-compound concentration >1.0 mcg/mL), (2) combined (parent-compound concentration <1.0 mcg/mL with combined itraconazole plus hydroxy-itraconazole >1.0 mcg/mL), and (3) subtherapeutic (failure to reach either threshold). Treatment response and adverse events were analyzed using the Fisher exact test. Results: Among 108 patients (parent, n = 40; combined, n = 40; subtherapeutic, n = 28), response rates differed across groups (parent (95%); combined (90%); subtherapeutic (67.9%); P = 0.006). There was no difference between the parent and combined groups. Adverse events did not differ, although drug discontinuation occurred more frequently in the subtherapeutic group (parent (5%); combined (20%); subtherapeutic (25%); P = 0.04). Conclusions: Patients who failed to achieve either an itraconazole concentration >1 mcg/mL or a combined itraconazole plus hydroxy-itraconazole concentration >1 mcg/mL had lower response rates. Similar outcomes among patients achieving the itraconazole target alone and those achieving the combined target suggest that hydroxy-itraconazole concentrations may contribute to therapeutic drug monitoring targets in histoplasmosis.

Introduction The integration of telehealth into clinical care has increased access to substance use disorder (SUD) treatment. However, drug screen monitoring has largely remained tied to in-person visits, preventing a fully virtual workflow. We evaluated the acceptability, appropriateness, feasibility, and usability of video-observed oral fluid (VOOF) self-collection as an approach to address this implementation gap. Methods Participants receiving SUD treatment in outpatient ( n = 13) or residential ( n = 15) settings completed a video-recorded oral fluid self-collection protocol, followed by the Acceptability of Intervention Measure, Intervention Appropriateness Measure, Feasibility of Intervention Measure, and System Usability Scale. Results Most participants had multiple SUDs ( n = 23, 82.1%), and nearly all had co-occurring mental illness ( n = 27, 96.4%). The majority completed study measures ( n = 23, 82.1%) and returned collection kits ( n = 25, 89.2%). Acceptability, appropriateness, and feasibility all exceeded established thresholds (&gt;3), with respective means of 3.5 (SD 1.1), 3.8 (SD 1.1), and 3.4 (SD 1.3). Usability scores were below average and more variable (mean = 51.8, SD 20.4). Scores did not significantly differ by care setting. Discussion This early-stage pilot found that VOOF self-collection was generally acceptable, appropriate, and feasible among individuals with SUD in real-world care settings. Usability scores were below average, with technical challenges related to video recording and upload likely contributing. Integrating VOOF within digital treatment platforms may streamline the user experience and improve usability while better aligning drug screen monitoring with the growth of telehealth in SUD treatment. This approach may benefit individuals experiencing transportation barriers and those in rural areas who live significant distances from testing sites.

Abstract Background Artificial intelligence (AI) augmented laboratory tests can improve quality, efficiency, cost-effectiveness, and staff satisfaction. However, the clinical success of these tests can introduce unforeseen challenges for model retraining. This study describes the discovery of an “AI label feedback loop” in a clinically implemented AI-augmented kidney stone composition test. Methods An AI-augmented kidney stone composition test (V1) has been previously deployed for clinical kidney stone characterization. After several years of clinical use, a retrained model (V2) was developed using 6 times more data. Model performance of both V1 and V2 were evaluated across 3 datasets: a recent production validation (hold-out) set (mostly AI-influenced labels), the original V1 validation set (pre-AI, entirely human-labeled), and a subset of recent cases with exclusively human-generated or human-corrected labels. Results V2 demonstrated a 10% lower concordance rate than V1 when evaluated on the recent production hold-out set, despite a much larger training dataset. Performance between V1 and V2 was similar when applied to the pre-AI validation set. Notably, V2 outperformed V1 on the recent subset of cases with human-only or human-corrected labels, particularly for less-common stone types. These findings revealed an AI label feedback loop, confounding retraining and evaluation. Conclusions The integration of AI into clinical practice can potentially influence reported test results, complicating the development and evaluation of future models. To mitigate AI label feedback loops, ongoing human annotation and careful validation set construction are essential. These strategies can ensure reliable performance assessment and support the safe evolution of clinical AI systems.

Abstract Background Alcohol biomarkers including ethyl glucuronide (EtG) and phosphatidylethanol (PEth) are ordered frequently in clinical and forensic settings including solid organ transplantation. PEth provides a long detection window but can be insensitive to light drinking. In contrast, EtG and ethyl sulfate (EtS) can be elevated after light alcohol consumption and might complement PEth testing. Methods Urine EtG/EtS and whole blood PEth results were evaluated from all clinically-ordered testing between 2014 and 2024. PEth and EtG/EtS confirmation were performed by liquid chromatography tandem mass spectrometry at two reference laboratories, using cutoffs: Lab A, PEth 20 ng/ml, EtG and EtS 500 and 250 ng/ml; Lab B, PEth 10 ng/ml, EtG and EtS 250 and 100 ng/ml. Only Lab B performed EtG screening by immunoassay, using a 500 ng/ml cutoff. Results Phosphatidylethanol was positive in 1269 (15.6%) of 8131 samples, compared to 769 (6.7%) confirmed EtG/EtS positives from 11 555 samples. EtG screening (n = 9668) was positive in 743 (7.7%) samples, of which 30 (4.0%) confirmed negative (false positives); the screen was indeterminate in 267 (2.8%) samples, 66 of which confirmed positive and 172 negative. Of 3132 paired PEth and EtG samples, 2887 (92.2%) were concordant, 224 (7.2%) were PEth-positive, and 21 (0.7%) were EtG-positive. PEth was significantly more sensitive in paired samples (P &lt; .001), even after accounting for potential confounders such as transfusion. Limiting testing to PEth would have correctly identified alcohol consumption in 331 of 373 (88.7%) instances versus EtG/EtS in 149 (39.9%), and reduced charges by &gt;$720 000 USD. Discussion Phosphatidylethanol outperformed EtG/EtS in detecting alcohol consumption in a predominantly abstinent transplant population. Compared to PEth, EtG/EtS had lower overall positivity and poorer sensitivity in paired samples; additionally, EtG screening demonstrated false positives and indeterminate results. EtG testing provided little added value beyond PEth in this population, and did not warrant the increased cost of performing both tests.

Abstract Purpose No consistent recommendations exist on how best to educate pharmacists to facilitate implementation of new evidence-based practices. This study aimed to determine whether spaced learning was more effective than traditional education when learning a new evidence-based practice (β-lactam therapeutic drug monitoring, or TDM). Summary β-lactam TDM was implemented in a phased fashion at Mayo Clinic in Rochester. Two go-lives took place, separated by 6 months, which allowed for a natural experiment to test education delivery methods (traditional education in the first go-live group of pharmacists vs spaced learning in the second go-live group of pharmacists). Each group received the same base educational package, with pharmacists in the spaced learning group also offered monthly in-person sessions for 6 months before go-live to discuss key considerations and cases with experts. There was no difference between the spaced learning group and the traditional education group when assessing appropriate use of TDM as defined by (1) appropriate patient selection; (2) correct ordering of laboratory testing; (3) appropriate clinical action; and (4) completed documentation. Assessments of secondary knowledge transfer also showed no difference between the groups. Pharmacists in the different education groups had similar satisfaction scores related to the effect and utility of the education. Both spaced learning and traditional education were part of a comprehensive implementation plan for β-lactam TDM, which might have influenced the outcomes. Spaced learning for future pharmacist education efforts needs further study. Conclusion As part of a greater β-lactam TDM implementation effort, altering the education delivery method did not impact the degree of knowledge transfer.

Abstract Background Loperamide is a µ-opioid receptor agonist that reduces intestinal peristalsis and is used to treat diarrhea. We previously described significant cross-reactivity of loperamide with 2 fentanyl immunoassays. Since then, new fentanyl immunoassays, including a CLIA-waived point-of-care device, have been approved for clinical use. Methods We evaluated new fentanyl immunoassays for cross-reactivity to loperamide and its major metabolites, N-desmethyl loperamide (dLop) and N-didesmethyl loperamide (ddLop). Previously characterized assays were tested for cross-reactivity to ddLop, which recently became commercially available. Loperamide, dLop, and ddLop were spiked in drug-free urine for analysis by 5 enzyme immunoassays run on automated chemistry analyzers and one lateral flow assay for the detection of fentanyl. Results Loperamide and its metabolites produced positive results in 3 fentanyl immunoassays. The Immunalysis HEIA was previously determined to be reactive to both loperamide and dLop, but it was not reactive to ddLop. The Immunalysis SEFRIA was reactive to loperamide, dLop, and ddLop at minimum concentrations of 14.7 mg/L, 13.1 mg/L, and 17.0 mg/L. The Thermo Fisher DRI was previously determined to be reactive to loperamide and dLop, and it was reactive to ddLop at a minimum concentration of 33.1 mg/L. The Abbott iCassette, ARK Fentanyl II, and Lin-Zhi LZI II fentanyl assays showed no cross-reactivity to loperamide or its metabolites. Conclusions The cross-reactivity of loperamide, dLop, and ddLop in several fentanyl immunoassays has the potential to cause false-positive results during urine drug screening.

Abstract Background We evaluated the Tecan Fluent Mix and Pierce Workstation as an automated platform to aliquot directly from whole blood collection tubes. The Fluent Mix and Pierce Workstation uses the Tube Rotator™, an on-deck rotisserie, to keep whole blood in suspension, and 8 Piercing Tips™ to cross the pierceable caps of collection tubes to aliquot samples. Methods We performed accuracy and precision testing by aliquoting residual whole blood specimens into an on-deck gravimetric scale. To test carryover, we aliquoted alternating blanks and high calibrators for several analytes and performed mass spectrometry on the blanks. We performed 168 runs over a 21-day period to test the robustness of the platform. We aliquoted and analyzed 2 batches of samples on both our clinical platform and the Mix and Pierce Workstation to check concordance. Results We observed that the Fluent Mix and Pierce Workstation can aliquot 200 µL with 0.5% inaccuracy and 0.9%CV and can aliquot 300 µL with 0.1% inaccuracy and 0.7%CV. We were unable to detect any analyte carryover using mass spectrometry. We observed no hardware failures during the instrument stress test. Clinical comparison runs indicated that the performance of aliquots made on the Fluent Mix and Pierce Workstation was equivalent to that of aliquots made by our current clinical method. Conclusions Overall, our evaluation showed that the Tecan Fluent Mix and Pierce Workstation is a viable platform for aliquoting whole blood for downstream work flows and can eliminate labor-intensive sample decapping and recapping in high-throughput settings.

Abstract Purpose/Background Clozapine requires careful monitoring to minimize adverse reactions and optimize response. Because of variable pharmacokinetics and interpatient variability, guidelines recommend therapeutic drug monitoring (TDM), although practical guidance is limited. This study aims to characterize patient factors associated with TDM, rates of TDM use over time, turnaround times of TDM results, and influence of institutional initiatives aimed to improve TDM. Methods/Procedures A retrospective chart review was conducted at a large 2000-bed academic medical center from August 1, 2015, to November 26, 2023. Adult patients who were administered clozapine during medical or psychiatric inpatient hospitalizations were included. Data collected included patient demographics, clozapine TDM ordering, and clozapine TDM turnaround time. Yearly TDM rates were analyzed to evaluate the impact of various institutional clozapine-related initiatives on TDM practices. Results There were 679 encounters involving 334 patients; 62.7 % were men, and 84.4% were White. Younger patients were less likely to have levels drawn (odds ratio 0.98, confidence interval 0.97–0.99), while self-identified Asian patients more likely (odds ratio 7.54, confidence interval 1.60–35.42). TDM rates increased significantly over time for both medical ( P = 0.002) and psychiatric ( P < 0.001) admission types, with turnaround times improving from 66.07 hours in 2016 to 28.65 hours in 2022. Overall, TDM annual rates increased from 46.2% in 2015 to 69.6% in 2023. The time-period before and after an institutional initiative, which improved TDM turnaround time, was associated with improvements of TDM rates (36.2% vs 67.9%, P < 0.001) Conclusions This study highlights an increase in clozapine TDM use during the study period, but use remained suboptimal. Improvement of turnaround time was associated with increased TDM rates.

OBJECTIVES: Estimated glomerular filtration rate is more accurate with combined creatinine and cystatin C equations (eGFRcr-cys) than creatinine alone. This study created and evaluated a cefepime dosing nomogram based on eGFRcr-cys for initial dosing in the critically ill. DESIGN: Pharmacokinetic modeling and simulation study. SETTING: Academic medical center. PATIENTS: Critically ill adults treated with cefepime. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Data from 120 patients with baseline cystatin C and follow-up cefepime levels were used to develop a nomogram based on eGFRcr-cys and weight for initial cefepime dosing. The predicted proportion of patients who achieved a free cefepime concentration above the minimum inhibitory concentration of the organism for 100% of the dosing interval in the first 24 hours (100% ƒT > MIC at 24 hr) was compared between administered doses and those predicted by the nomogram doses. Overall drug exposure was estimated with the free area under the concentration time curve from 0 to 24 hours (ƒAUC0–24) and compared between administered and nomogram doses. Achievement of 100% ƒT > MIC at 24 hours was predicted to be significantly better with the nomogram compared with the administered dose (76% vs. 38%; p < 0.001). The median ƒAUC0–24 as predicted by the nomogram (666 mg·hr/L) was slightly higher than the actual ƒAUC0–24 with administered doses (612 mg·hr/L; p = 0.01), but the nomogram led to fewer ƒAUC0–24 values which were either too high (> 900) or too low (< 300) (7% vs. 20%; p = 0.004). CONCLUSIONS: Use of a cystatin C-inclusive dosing nomogram for cefepime could improve target attainment without increasing the risk of potentially toxic levels in the critically ill.

AbstractBackground and ObjectivesWhen administered as prescribed, the naloxone component of buprenorphine‐naloxone combination medications is putatively considered inert due to reduced naloxone bioavailability via transmucosal. However, there is a growing body of evidence to the contrary. The aim of our study is to determine the extent of naloxone absorption in a large cohort of patients receiving sublingual buprenorphine‐naloxone.MethodsUsing the Mayo Clinic Unified Data Platform, 425 patients prescribed sublingual buprenorphine/naloxone who received a controlled substance monitoring panel (CSMP) between January 1, 2022, and January 1, 2023 were identified and included. The CSMP is an immunoassay panel that confirms positive results quantitatively with gas chromatography mass spectrometry or liquid chromatography tandem mass spectrometry. This panel provides urinary detection for buprenorphine (cutoff: 5 ng/mL), naloxone (25 ng/mL), as well as their respective metabolites norbuprenorphine (5 ng/mL), norbuprenorphine‐glucuronide (20 ng/mL), and naloxone‐glucuronide (100 ng/mL).ResultsOf our 425 patients, 76% had norbuprenorphine (n = 323), and 77% had norbuprenorphine‐glucuronide (n = 327) in their toxicology tests, respectively. Naloxone‐glucuronide was detected in 91% (n = 294) of the specimens with norbuprenorphine and 88.7% (n = 290) of the specimens with norbuprenorphine‐glucuronide.Conclusion and Scientific SignificanceTo our knowledge, this is the largest study to date demonstrating the presence of naloxone metabolites in patients taking combined buprenorphine‐naloxone medications. The results of this study refute the notion that naloxone absorption is negligible when administered in sublingual preparations. Further research on how this absorption impacts medication usage, dosing, adherence, and side effects is necessary.