Maus, Anthony

Abstract Disclosure: C.A. Villavicencio Torres: None. S. Ahmadian: None. K. Moehnke: None. V.M. Fell: None. R.L. Taylor: None. S.K. Grebe: None. A.D. Maus: None. I. Bancos: None. Background: Evaluation of adrenal disorders relies on total cortisol measurements at baseline or during dynamic testing. Accurate cortisol assessment that avoids phlebotomy may simplify the work up of adrenal disorders, decrease healthcare costs, and improve patient experience. Objectives: We aimed to compare cortisol and dexamethasone concentrations between venipuncture-based (clinical) and capillary blood samples. Methodology: We conducted a cross-sectional study (July 2024-April 2025) of adults undergoing standard-of-care cortisol measurements. Capillary blood samples were collected alongside clinical samples. Capillary measurements included total cortisol and dexamethasone (mass spectrometry). Clinical samples were tested for total cortisol (Roche immunoassay) and dexamethasone (mass spectrometry). Results: Of 318 patients (243, 77% women, median age 53 years, IQR 39-66), 227 (71%) underwent dexamethasone suppression test (DST) and 88 (28%) cosyntropin stimulation test (CST). Capillary blood collection failed in 13 (4%) patients. In patients undergoing DST, median post-dexamethasone serum cortisol was 1.3 mcg/dL (IQR 0.8-2.2), and serum dexamethasone was 0.41 mcg/dL (IQR 0.27-0.59), while median capillary cortisol was 1.5 mcg/dL (IQR 1-2.5), and capillary dexamethasone was 0.33 mcg/dL (IQR 0.21-0.51). Capillary cortisol (r=0.95, 95% CI [0.93, 0.96], p<.0001) and capillary dexamethasone (r=0.93, 95% CI [0.90, 0.95], p<.0001) showed strong correlation with their respective clinical measurements. In patients undergoing CST, median baseline serum cortisol was 7.5 mcg/dL (IQR 5-10), and median baseline capillary cortisol was 8.5 mcg/dL (IQR 6-12). Median post-CST 60-minute serum cortisol was 23 mcg/dL (IQR 20-25), while capillary cortisol was 25 mcg/dL (IQR 21-28). Baseline (r=0.77, 95% CI [0.66, 0.85], p<.0001) and post-CST 60-minute capillary cortisol (r=0.88, 95% CI [0.81-92], p<.0001) strongly correlated with clinical measurements. Post-dexamethasone cortisol in paired DST samples showed that capillary measurements were higher than serum cortisol (median difference 0.20 mcg/dL (95% CI [0.12, 0.42], p<.0001), while paired capillary dexamethasone concentrations were lower than serum dexamethasone concentrations (median difference 0.04 mcg/dL (95% CI [0.03, 0.07], p<.0001). In CST, paired baseline capillary and serum cortisol concentrations were similar (median difference 0.10 mcg/dL, 95% CI [0.3, 0.3], p=.3660), while paired post-CST 60-minute capillary cortisol was higher than serum cortisol by a median of 2.8 mcg/dL (95% CI [2, 3.2], p<.0001). Conclusion: Capillary cortisol and dexamethasone concentrations demonstrate excellent correlation with venipuncture-based measurements. Following validation with at-home collection, capillary blood measurements may serve as an alternative for evaluating adrenal disorders. Presentation: Sunday, July 13, 2025

Abstract Disclosure: C.A. Villavicencio Torres: None. S. Ahmadian: None. V.M. Fell: None. K. Moehnke: None. Y. Chai: None. R.L. Taylor: None. S.K. Grebe: None. A.D. Maus: None. I. Bancos: None. Background: Current standard-of-care assessment of adrenal disorders relies on the venipuncture-based total cortisol measurements. Salivary cortisol (SalF) and cortisone (SalE) measurements have advantages such as a more accurate assessment of patients with cortisol-binging globulin abnormalities and the convenience of at-home non-invasive testing. Aims: This study aimed to compare concentrations of cortisol and dexamethasone between clinical (venipuncture-based) and saliva samples. Methodology: We conducted a cross-sectional study (July 2024-January 2025) of adults undergoing overnight dexamethasone suppression test (DST) or cosyntropin stimulation test (CST). Saliva samples were collected alongside clinical samples. Saliva measurements included cortisol, cortisone, and dexamethasone (mass spectrometry), while clinical samples were tested for total cortisol (Roche immunoassay) and, in a subgroup, dexamethasone (mass spectrometry). Results: Of 241 patients (186 (77%) women, median age 53 years (IQR 39-66)), 178 (74%) provided samples as a part of DST and 63 (26%) as a part CST. An inability to provide sufficient saliva for analysis was found in 5 patients (2%). In patients undergoing DST, median post-dexamethasone serum total cortisol was 1.3 mcg/dL (IQR 0.8-2.2), and median serum dexamethasone (SerD) was 0.43 mcg/dL (IQR 0.3-0.6) based on clinical samples, while median SalF was 10.2 ng/dL (IQR 6.6-23.6), SalE was 78.6 ng/dL (IQR 52.8-131.1), and saliva dexamethasone (SalD) was 60 ng/dL (IQR 41-93). SalE (r=0.92, p<.0001) demonstrated a stronger correlation than SalF (r=0.85, p<.0001) when compared with post-dexamethasone serum total cortisol measurements. SalD (r=0.85, p<.0001) correlated with SerD measurements. In patients undergoing CST, median baseline serum total cortisol was 7.2 mcg/dL (IQR 4.6-10) based on clinical samples, while median baseline SalF was 86.6 ng/dL (IQR 38.3-166.3), and median SalE was 707 ng/dL (IQR 347-906). Median peak 60-minute serum total cortisol was 21.5 mcg/dL (IQR 18-24), while SalF was 870.4 ng/dL (IQR 440-2904) and SalE was 2501 ng/dL (IQR 1770-3193). Both baseline (r=0.92, p<.0001) and 60 min peak post-cosyntropin SalE (r=0.84, p<.0001) demonstrated a strong correlation with venipuncture-based measurements. SalF had a weaker than SalE correlation at both baseline (r=0.88, p<.0001) and 60 min peak post-cosyntropin (r=0.79, p<.0001). Conclusion: Our study demonstrates that salivary measurements of cortisone, cortisol and dexamethasone strongly correlate with standard-of-care venipuncture concentrations following DST and CST. SalE showed the stronger than SalF correlation with venipuncture-based serum total cortisol concentrations. Presentation: Sunday, July 13, 2025

Abstract Disclosure: S. Ahmadian: None. S.R. Chacko: None. S. Sharma Sharma: None. V.M. Fell: None. A. Peersen: None. E.J. Atkinson: None. K.L. Moehnke: None. Y. Chai: None. S.K. Grebe: None. A.D. Maus: None. I. Bancos: None. Background: Cortisol secretion follows a circadian pattern with highest concentrations in the morning, and lowest at night. Loss of circadian cortisol variation has been reported in patients with Cushing syndrome (CS), however, is scarcely investigated in patients with mild autonomous cortisol secretion (MACS). Outpatient assessment of late night and early morning salivary cortisol and cortisone may serve as a valuable diagnostic tool in patients with hypercortisolism. Methods: We conducted a single-center cross-sectional study of adults evaluated at our center between 04/2024 and 04/2025. The study included patients with Cushing’s syndrome (CS), mild autonomous cortisol secretion (MACS), and referent subjects without known adrenal disorders. Participants were provided with two cotton swabs (Salivettes) and instructed to collect saliva samples at two standardized time points: at bedtime (PM) and on waking (AM). Each swab was kept in the mouth for 2-2.5 minutes. Saliva was analyzed for cortisol and cortisone using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Delta cortisol and delta cortisone were defined as the difference between AM and PM concentrations for each individual and were calculated for all participants. Results: A total of 82 patients (32 with ACTH-dependent CS, 5 with ACTH-independent CS, and 45 with MACS), median age of 55 years [IQR 44-65], 63 (77%) women, and 71 referent subjects, median age of 34 years [IQR 28-42], 54 (76%) women, were included. Delta cortisol was higher in referents (median of 212 ng/dL, [IQR 157-358]) vs patients with CS (median 95 ng/dL [IQR -21-184]) or MACS (median 131 ng/dL, [IQR 91-229]). Similarly, delta cortisone was also highest in referents with a median of 828 ng/dL [IQR 612-1131] versus median of 211 ng/dL [IQR -58-468] in CS and 484 ng/dL [IQR 189-849] in MACS. When compared to referents in an age- and sex-adjusted linear regression model, delta cortisone was lower in both patients with CS (est -1.3 (95%CI -1.75 to -0.85), P<0.001 and MACS (est -0.66, 95%CI of -1.17 to -0.16, P=0.010). Delta cortisol was lower in patients with CS (est -1.32, 95%CI -2.11 to -0.54, P=0.001), but not MACS (est -0.51, 95%CI -1.39 to 0.36). Conclusion: Patients with both CS and MACS demonstrate a blunted circadian salivary cortisol and cortisone secretion, as reflected by a lower delta cortisol and cortisone when compared to referent subjects. Assessment with delta salivary cortisone in patients with MACS may be more valuable than a standard of care late night salivary cortisol assessment. Presentation: Sunday, July 13, 2025

Abstract Disclosure: S. Ahmadian: None. C.A. Villavicencio Torres: None. V.M. Fell: None. K.L. Moehnke: None. Y. Chai: None. R.L. Taylor: None. S.K. Grebe: None. A.D. Maus: None. I. Bancos: None. Background: Salivary cortisol (SalF), and cortisone (SalE) interpretation can be influenced by intra-individual variability arising from cortisol secretion cyclicity, assay performance, and sampling techniques. No studies to date have examined the impact of sampling on intra-individual variability. Methods: We conducted a single-center cross-sectional study of adults evaluated with total serum cortisol measurements as a part of the overnight dexamethasone suppression test (DST) or cosyntropin stimulation test (CST), November 2024- January 2025. Participants were provided with two cotton swabs (salivettes) and asked to collect two consecutive saliva samples immediately after the venipuncture for total cortisol. Each cotton swab was kept in the mouth for 2-2.5 minutes. Saliva was tested for SalF and SalE by mass spectrometry. Variability was examined based on cortisol tertiles. Results: A total of 78 paired saliva samples were obtained from 60 participants (45 [75%] women; median age 55 years [IQR 39-66]), who were undergoing either DST (42 [70%]) or CST (18 [30%]). A total of 10 (17%) saliva samples did not contain a sufficient sample for analysis during the first or second saliva collection (7 [12%] from DST group, and 3 [5%] from CST group).Among 53 patients undergoing DST, the median serum total cortisol was 1.3 mcg/dL [IQR 0.9-3], the median first SalF was 20 ng/dL [IQR 7-28], the median second SalF was 12 ng/dL [IQR 6-23], and the median variability was 11% [IQR 3-22%]. The median first SalE was 69 ng/dL [IQR 54-185], while the median second SalE was 63 ng/dL [IQR 56-178], with a median variability of 6% [IQR 4-10].In patients undergoing CST, peak median serum total cortisol was 20 mcg/dL [IQR 18-24], median first SalF was 809 ng/dL [IQR 536-1227], and median second SalF was 1063 ng/dL [IQR 667-1503], with the median variability of 14% [IQR 8-22]. The median first SalE was 2507 ng/dL [IQR1697-2966], while the median second SalE was 2485 ng/dL [IQR 1530-2976], with a median variability of 9% [IQR 3-12].When examining intra-individual variability of SalF, the variability was lowest in the middle tertile, corresponding to serum cortisol of 1.8-8.9 mcg/dL, at 9% [IQR 5-16]. Variability was higher in the lowest tertile (14% [IQR 0-52]) and the highest tertile (12% [IQR 6-16]). Overall, the variability of SalE was lower than that of SalF: 7% [IQR 4-13] in the lowest tertile, 5% [IQR 2-9] in the middle tertile, and 10% [IQR 4-12] in the highest tertile. Conclusion: We show that saliva sampling may impact the results, with 17% patients providing insufficient sample for analysis, and variability of 9-14% for SalF and 5-10% for SalE. Same time-point sampling-related variability should be considered in interpretation of SalF and SalE measurements. Presentation: Sunday, July 13, 2025

Abstract Thyroglobulin (Tg) is a 330-kDa homodimeric protein that that is the prohormone of thyroid hormones triiodothyronine (T3) and thyroxine (T4). The most critical steps of thyroid hormone synthesis by Tg are iodination and fusion of specific tyrosine residues that are in close proximity to each other in the folded Tg protein. The degree of Tg iodination has been studied widely to determine if it is correlated with thyroid autoimmune disease with mixed results, but these efforts have been limited by the lack of an effective quantitative technique. Simultaneously, the treatment of thyroid cancer has undergone a shift toward partial thyroidectomies, thus undermining the value of Tg measurements. A possible alternative to established monitoring techniques is measurement of Tg iodination states as it has been shown that tumor-derived Tg has significantly lower iodine content. Such measurements require a thorough understanding of normal iodination status. In this study, state-of-the-art liquid chromatography–tandem mass spectrometry (LC-MS/MS) instrumentation is used to perform bottom-up proteomics experiments and identify iodinated residues within commercially available Tg. Using this technique, sequence coverages greater than 90% were achieved, which resulted in identification of previously identified and novel hormone synthesis and donor sites. Based on the results of these discovery experiments, 5 iodination sites were selected for targeted quantitative LC-MS/MS measurements, which suggested that hormone synthesis occurs predominantly at Y24 and Y2766. The results presented herein lay the foundation for routine measurements of iodinated residues, which has the potential to overcome the limitations of current monitoring techniques and benefit patient care.

Abstract Background Factitious hypoglycemia, a deliberate attempt to induce low blood glucose levels occurring secondary to the surreptitious administration of exogenous insulin, can be difficult to diagnose due to a variety of factors including the increased use of synthetic insulin analogs in clinical practice. Traditional insulin immunoassays demonstrate variable cross-reactivity with commonly prescribed insulin analogues and their metabolites, making it difficult to measure specific analogs. The development of liquid chromatography high resolution accurate mass (LC-HRAM)-mass spectrometry (MS) assays has largely circumvented the limitations of traditional immunoassays for detection and quantitation of insulin analogs. Analytical challenges remain, however, specifically in differentiating lispro, an isomeric human insulin analog formed by the transposition of proline and lysine near the C-terminal end of the B chain, from human insulin in patient samples due to the equivalent mass-to-charge ratios of their precursor ions. Methods Immunoaffinity purification of insulin from calibrators and quality control material prepared by spiking insulin-depleted serum with pharmaceutical insulin preparations, as well as patient samples, was performed using tips coupled with anti-insulin monoclonal antibody. An automated liquid handler was programmed to perform aspiration and dispense cycles. Eluate from the purification protocol was submitted for analysis using a TLX-2 multiplex LC system paired with a Thermo Scientific Q Exactive Plus mass spectrometer. Various HPLC column chemistries were evaluated, a column passivation procedure was established, and column heater temperature was optimized to identify a combination of parameters yielding the best chromatographic separation of human insulin and lispro. Additionally, parallel reaction monitoring (PRM) targeted tandem mass spectrometry (MS/MS) analysis was utilized in combination with the full scan data to increase specificity through the monitoring of fragment ions produced from human insulin and each insulin analog. Results We found that a 1000 Å Diphenyl, 2.7 µm, 2.1 x 100 mm analytical column in a column heater maintained at a temperature of 80°C allowed for human insulin and lispro to be differentiated as two chromatographically separated extracted ion chromatographic peaks (XICs) and quantified down to 2.5 mcIU/mL with near-baseline separation. Before use, the column required passivation with a high protein buffer (0.05% bovine serum albumin in 20% acetonitrile [ACN] + 0.2% acetic acid) followed by increasingly organic buffers (20% ACN + 0.2% acetic acid and 50% ACN + 0.2% acetic acid). MS/MS was used to confirm the presence of analogs detected. Conclusions The LC-HRAM-MS method described here, coupled with optimized column chemistry, column passivation, and proper column temperature control allows for chromatographic separation of human insulin and lispro. Incorporating a PRM scan into the mass spectrometry full scan method provides confirmation of the insulin detected in the XICs. The results obtained from preliminary studies suggest this method is appropriate for use to facilitate the clinical investigation of suspected factitious hypoglycemia with the ability to differentiate isomeric compounds, such as human insulin and lispro.

Abstract Background Our established method for measuring plasma catecholamines utilized a Shimadzu HPLC coupled to an ESA Coulochem III electrochemical detector. Chromatographic run times were long, resulting in slow turnaround times. Instrument maintenance was labor intensive, and the assay was prone to interferences. To overcome these limitations, we changed the method to liquid chromatography-tandem mass spectrometry (LC-MS/MS) measurements. Methods After the addition of a labeled internal standard for each analyte, samples are loaded onto 50 mg of activated alumina at pH 8.6, utilizing a Tris-HCl, sodium carbonate and EDTA buffer. After incubation the alumina is then washed with 50% acetonitrile followed by water. Elution off the alumina is performed with 2% acetic acid. Derivatization is then performed on the eluate utilizing acetaldehyde and a cyanoborohydride buffer. Following derivatization, the samples are analyzed for epinephrine, norepinephrine, and dopamine by LC-MS/MS using a Sciex 7500 coupled to a ThermoFisher Scientific TLX-4 equipped with Vanquish pumps. Chromatographic separation was obtained using a Phenomenex Kinetex 2.6 um BiPhenyl 50x3 mm analytical column. Results Runtimes were significantly shorter than with the previous method, and no interferences were observed. Assay validation consisted of: intra/inter assay precision, accuracy, recovery, linearity, carryover, limit of detection (LOD), and interferences. Three levels were assessed for intra assay precision and each of the analytes monitored yielded %CVs of less than 6%. Four levels were assessed for inter assay precision and each of the analytes monitored yielded %CVs of less than 10%. When using linear regression analysis to compare results with the previous clinical assay, the slope, y-intercept and R2 were the following; dopamine: 1.06, 2.74, 0.978; epinephrine: 0.905, 2.20, 0.989; norepinephrine: 0.919, 9.75, 0.953. Spike and recovery from five samples yielded a mean average recovery of 93.4% for dopamine, 100% for epinephrine and 98.1% for norepinephrine. For linearity 4 samples were diluted and the mean % difference from expected was -1.66% for dopamine, -0.25% for epinephrine and 1.78% for norepinephrine. Blanks were injected following the high standard and carryover was negligible. LOD was determined by running a low sample pool along with a blank over 20 assays. The LOD was determined to be less than the LLOQ. Sixty-two common drugs/vitamins along with varying levels of hemolysis, lipemia, and bilirubin were also tested to ensure no interferences were seen. Conclusions The LC-MS/MS method exceeded the performance of the historical Shimdazu HPLC system with ESA Coluochem III electrochemical detector method. We anticipate that the better analytical performance will improve the testing quality of our patients.

Abstract Background The legality and use of marijuana is a controversial topic. With increased prevalence of usage, cannabis detection for legal, medical, and workforce drug testing is on the rise. LC-MS/MS quantification of delta 9-carboxy tetrahydrocannabinol (delta 9-THC-COOH) in urine is accepted as the standard to detect marijuana use. One challenge faced by testing laboratories has been identifying adulterated samples. Many products/reagents can be used to manipulate the urine to avoid positive drug testing results. In this study, we developed a dilute-and-shoot strategy to separate and quantify both the delta 8- and 9-THC-COOH in urine samples and tested the effects of adulteration using a combination of nitrite and/or acids which can be used to mask cannabinoid use. Methods Five authentic delta 8- and 9-THC-COOH positive specimens, and one spiked sample were treated with strong acids (1N HCL or 10% TCA), 500 µg/mL nitrite, or a combination. After hydrolysis with sodium hydroxide, the analytes were quantified using a 6495 Mass Spectrometer coupled to a StreamSelect LC system (Agilent). LC separation was performed with a CORTECS T3 column utilizing a shallow gradient. In addition, twelve urine specimens with varying concentrations of delta 8- and 9-THC-COOH were treated with nitrite and screened using a delta 9-THC-COOH immunoassay on the Roche Cobas C501 and analyzed by LC-MS/MS. Results Nitrite did not change the physical appearance or the pH of the urine samples. Strong acid treatment also did not alter the appearance but did drop the urine pH ≤2. Pre-treated specimens with 1N HCL, 10% TCA, or 500 µg/mL of nitrite did not affect the delta 8- and 9-THC-COOH concentrations up to 6 days (refrigerated); however, specimens treated with strong acid combined with 500 µg/mL of nitrite for 30 min made both analytes undetectable. Additional experiments confirmed that 0.5 and 1 mol/L of nitrite lowered the concentration of all analytes, including internal standard, to undetectable levels in 48 h. Twelve additional specimens were collected, 3 with delta 8-THC-COOH, 3 with delta 9-THC-COOH, and 6 with both. All 12 samples screened positive using the Roche immunoassay and were quantified using the LC-MS/MS method. After treatment with 0.5 mol/L of nitrite, 10 of the 12 samples were negative using the immunoassay, but 2 samples remained positive. However, all nitrite treated specimens were negative (<LLOQ) using the LC-MS/MS method and the internal standard was eliminated. Later experiments confirmed that the delta 8- and 9-THC-COOH could be eliminated with as little as 0.1 mol/L nitrite for 30 min. Conclusion The unique dilute-and-shoot method can separate and quantify delta 8- and 9-THC-COOH. In addition, high concentrations of nitrite were shown to degrade both analytes along with the isotopically labeled internal standard. As a result, labs can distinguish true negative delta 8- and 9-THC-COOH (no analyte peaks) from nitrite adulterated specimens since the adulterated samples have no peaks for both the analytes and internal standard. A limitation of the study is that only sodium nitrite was tested. Other adulterants, such as potassium nitrite, pyridinium chlorochromate, peroxide etc. require further investigation.