1. Background

Modern IVD assays require human specimens that span the analytical measurement range (AMR) at clinically meaningful concentrations to validate sensitivity, specificity, precision, linearity, and clinical reportable range. Many of the analytes in routine therapeutic-drug-monitoring and endocrinology workflows have concentrations that depend on dose timing, physiology, pregnancy status, and disease state — producing a multi-axis sampling problem that a single fixed-cohort study does not solve.1

This protocol sponsors a multi-analyte, multi-concentration-range specimen-collection program covering 27 cohorts in five therapeutic categories, each enrolled across Low, Medium, and High concentration ranges. Eligible subjects are identified via two parallel mechanisms — clinical-laboratory-data-driven physician identification under a Preparatory-to-Research determination, and traditional feasibility / specialty outreach — and consent at a single 30 to 60-minute visit. Up to 150 mL of whole blood is collected per visit; subjects may re-consent into additional cohorts subject to a minimum 8-week inter-visit interval. The protocol authorises up to 2,000 subjects across the cohort matrix over a planned 24-month window. Specimens are processed and stored by RDI and provided to a downstream IVD client for analytical validation under separate protocols.

2. Constraints encountered

Five constraints shaped the execution plan:

  1. Holiday-window IRB pursuit

    The protocol was filed with Advarra on 24 December 2025 — the eve of the U.S. Christmas holiday window. IRB review timelines through the late-December and early-January window typically run materially longer than the standard 7–15 day cycle observed in other studies in the same engagement series. The 21-day end-to-end IRB cycle includes the U.S. holiday days when central IRB throughput is lower.

  2. Multi-axis cohort structure

    The protocol enrolls across 27 analyte cohorts × 3 concentration ranges (Low / Medium / High), giving 81 nominal sub-cohort slots. Each (analyte, range) combination has its own clinical-signature definition: for example, the Cortisol Low cohort criteria include adults with midnight or evening sample, dexamethasone-suppression-test subjects, or adrenal-insufficiency subjects donating before their morning glucocorticoid dose; the Cortisol High cohort criteria include recently-diagnosed Cushing syndrome, late-third-trimester pregnancy, or cortisol-secreting adrenal carcinoma. Operationally each (analyte, range) combination behaves as its own sub-study with its own screening signature.2

  3. Concentration-range identification, not just analyte presence

    Subjects are eligible if they meet the analyte-and-range cohort definition by physiology, dose timing, disease state, or recent laboratory result — not simply by the presence of the analyte. The Investigator pre-screens prospective subjects against the criterion (under a Partial Waiver of HIPAA Authorization for the chart-review step) and confirms the predicted concentration range before consent. The screening-to-enrollment conversion ratio depends on the precision of the pre-screen against the cohort-range criterion.

  4. Lead-site density requirement across categories

    The five therapeutic categories pull from different patient populations: hormones from endocrinology and women’s health; immunosuppressants from solid-organ transplant recipients; anti-epileptics from neurology; antifungals from infectious disease; antibiotics from inpatient and ICU settings. No single site covers all 27 cohorts; the lead-site network has to be selected for category overlap with site-specific cohort access.

  5. Concurrent sister-program scope

    The program ran concurrent with a sister transplant therapeutic-drug program (reported in Vol. 2026, No. 03 of this series) opening Collection II at the same Tier-1 lead sites. Site-level coordinator capacity, IRB amendment scheduling, and shipping logistics had to be balanced across both programs without one starving the other of operational throughput.

Each (analyte, range) combination has its own clinical-signature criterion. The protocol authorises up to 2,000 subjects — meaning the average cohort × range slot accommodates roughly 25 enrollments — over a 24-month planned window.

3. Methods

RDI executed the program as sponsor of record from the Van Nuys operational spine. Five operational moves are reported here in order of implementation.

3.1. Holiday-window IRB pursuit

The Advarra IRB application was filed 24 December 2025; IRB review cleared 14 January 2026 — 21 days end-to-end across the U.S. holiday window. Approval documents were posted 9 February 2026. The 21-day cycle includes the late-December and early-January days when central IRB throughput is lower; the same review running across a non-holiday window would have closed in 7–15 days, consistent with other 2025–2026 IRB cycles in this engagement series. Filing on 24 December rather than waiting until early January traded ~3 weeks of calendar time for ~2 weeks of effective review time and accelerated site activation by approximately three weeks.

3.2. Wave-based therapeutic-category sequencing

The 27-cohort matrix was sequenced into therapeutic-category waves to manage operational capacity at the lead sites. Wave 1 covered the three hormone cohorts (testosterone, aldosterone, cortisol) plus mycophenolic acid as a representative immunosuppressant; Wave 2 opens the 12 anti-epileptic cohorts at additional sites with neurology-clinic access; subsequent waves bring in the remaining immunosuppressants and oncology agents (tacrolimus, cyclosporine, sirolimus, everolimus, mycophenolic acid glucuronide, methotrexate) and the antifungal and antibiotic categories. The sponsor may close enrollment to specific cohorts or concentration ranges at any time based on recruitment status or scientific considerations.

3.3. Two-mechanism subject identification

Subject identification used two parallel mechanisms. The first — clinical-laboratory-data-driven physician identification — partners with a clinical laboratory to review test-ordering patterns identifying physicians whose patient populations meet specific cohort criteria; the laboratory either provides physician contact information to RDI or sends an IRB-approved informational letter on behalf of RDI. No patient-level Protected Health Information is shared in this step. The second — traditional feasibility outreach — uses RDI’s clinical-collaborator network, public physician directories, claims-based specialty mapping, and referral-from-investigator pathways to identify potential investigator-physicians.

3.4. Lead-site activation: 5 sites in 6 weeks

Five sites were activated by the 30 April 2026 reporting date: Site A (lead, multi-cohort), Site B (cortisol-eligible cohort access), Site C (internal validation cohort), Site D (multi-cohort), and Site E (specific-analyte access). Three additional sites are advancing through SIV for Wave 2 (anti-epileptic) cohort opening: Site F, Site G, and Site H. The same network architecture as the sister transplant therapeutic-drug program is used where useful, with cohort-specific additions for analyte categories not covered at the transplant network.

3.5. Single-visit, up-to-150-mL design

The protocol uses a single-visit design (30–60 minutes) with up to 150 mL of whole blood collected via standard venipuncture, with the actual volume determined by analyte requirements and Investigator clinical judgment per subject. Subjects may be re-consented into additional cohorts after an 8-week inter-visit interval. The single-visit architecture minimises the number of subjects who must undergo study procedures; the 8-week re-enrollment gate manages the total blood-volume burden within standard whole-blood-donation safety limits.

Longitudinal therapeutic-drug monitoring (sister program)

Solid-organ transplant recipients on prescribed regimens; peak/trough draws across multi-month visit-series; tiered Tier-1 + Tier-2 + Tier-3 site network. Unit of work: the patient over time.

This program

Concentration-range-defined cohort × analyte specimen bank; single 30–60 minute visit per cohort; 8-week re-enrollment gate. Five lead sites across endocrinology, transplant, and neurology pulls. Unit of work: the cohort × range slot.

4. Results

Cumulative enrollment crossed 25 by end-February 2026, 59 by end-March 2026, and reached 102 at the 30 April 2026 reporting date (Fig. 1). Monthly enrollment ran at +25, +34, +43 across the three full months of program activity, indicating a continued steady ramp consistent with progressive Wave 1 cohort closures.

Site distribution at the 30 April reporting date: Site A (40), Site B (22), Site C (22), Site D (17), and Site E (2). Wave 1 closures (hormones plus mycophenolic acid) achieved the first protocol-defined milestone deliverable (MDP1). The cortisol cohort fully closed against its protocol target with the final subject collected at one of the lead sites; testosterone, aldosterone, and mycophenolic acid continue to track toward range-specific targets (Table 1).

The 27-cohort × 3-range matrix is shown in Fig. 2 and listed in Table 2, with the four Wave 1 cohorts highlighted at MDP1 and the 12 Wave 2 anti-epileptic cohorts shown as opening. The remaining 11 cohorts (six immunosuppressant / oncology, voriconazole, and four antibiotics) are sequenced into subsequent waves per the analyte plan.

Table 1 Site contribution at the 30 April 2026 reporting date. The five active sites support the four Wave 1 cohorts (testosterone, aldosterone, cortisol, mycophenolic acid); Wave 2 anti-epileptics opens at three additional sites (Sites F, G, H) following SIV.
Site Cohort access Enrolled Status
Site AMulti-cohort lead (hormones + ISD)40Active
Site BCortisol-eligible cohort access22Active
Site CInternal validation cohort22Active
Site DMulti-cohort (hormones)17Active
Site ESpecific-analyte access2Active
Active subtotal5 sites103—
Site FWave 2 anti-epileptic neurology—SIV
Site GWave 2 anti-epileptic neurology—SIV
Site HWave 2 anti-epileptic pediatric / adult—SIV
All sites at 30 Apr 2026 reporting date5 active / 3 in SIV102Wave 1 + Wave 2
Table 2 Full 27-cohort matrix authorised under the protocol. Each cohort enrolls across Low, Medium, and High concentration ranges spanning the analytical measurement range; concentration-range definitions reference the protocol’s clinical-signature criteria (e.g., dose timing, physiology, disease state, recent laboratory result). The orange highlight indicates Wave 1 cohorts at MDP1 as of 30 April 2026; the navy highlight indicates the cohort fully closed against its protocol target.
Therapeutic category Analyte cohort Conc. ranges Wave
Hormones (steroids)Testosterone — MDP1Low / Med / HighWave 1
Aldosterone — MDP1Low / Med / HighWave 1
Cortisol — cohort closed at MDP1Low / Med / HighWave 1
Immunosuppressants / oncologyTacrolimusLow / Med / HighWave 3+
CyclosporineLow / Med / HighWave 3+
SirolimusLow / Med / HighWave 3+
EverolimusLow / Med / HighWave 3+
Mycophenolic acid (MPA / MMF) — MDP1Low / Med / HighWave 1
Mycophenolic acid glucuronideLow / Med / HighWave 3+
MethotrexateLow / Med / HighWave 3+
Anti-epileptics (AEDs)GabapentinLow / Med / HighWave 2
Phenytoin (total)Low / Med / HighWave 2
Phenytoin freeLow / Med / HighWave 2
Valproic acid (total)Low / Med / HighWave 2
Valproic acid freeLow / Med / HighWave 2
LevetiracetamLow / Med / HighWave 2
PhenobarbitalLow / Med / HighWave 2
LamotrigineLow / Med / HighWave 2
TopiramateLow / Med / HighWave 2
PrimidoneLow / Med / HighWave 2
CarbamazepineLow / Med / HighWave 2
ZonisamideLow / Med / HighWave 2
AntifungalsVoriconazoleLow / Med / HighWave 3+
AntibioticsAmikacinLow / Med / HighWave 3+
GentamicinLow / Med / HighWave 3+
TobramycinLow / Med / HighWave 3+
VancomycinLow / Med / HighWave 3+
5 categories27 analyte cohorts81 sub-cohorts3 waves
0 50 100 150 200 CUMULATIVE ENROLLMENT (n) Jan Feb Mar Apr May Jun Jul … Calendar month, Jan 2026 – Jul 2026 (Wave 1 + Wave 2 forecast) 102 · 30 APR 2026 IRB CLEARED 14 Jan 2026 CORTISOL CLOSE / MDP1 April 2026 forecast (Wave 2 anti-epileptics open)
Fig. 1 Cumulative enrollment, January through April 2026 (solid line, actual), with forecast extension into Wave 2 (dashed). The 21-day IRB-clearance window across U.S. holidays is annotated; the cortisol-cohort closure and MDP1 achievement at end-April mark the formal close of Wave 1 cohorts at concentration-range targets. Source: RDI Salesforce enrollment dashboard (FY2026); sponsor bi-weekly project-update reports (Feb–May 2026).
27-COHORT MATRIX BY THERAPEUTIC CATEGORY AND WAVE WAVE 1 (active) WAVE 2 (opening) WAVE 3+ (planned) Hormones 3 cohorts Testosterone (MDP1) Aldosterone (MDP1) Cortisol (closed) Imm./oncology 7 cohorts MPA (MDP1) Tacro / Cyclo / Siro / Evero MPAG / Methotrexate Anti-epileptics 12 cohorts Gabapentin · Phenytoin (T+F) Valproic (T+F) · Levetiracetam Phenobarb · Lamotrigine Topira · Primid · Carba · Zoni Antifungals 1 cohort Voriconazole Antibiotics 4 cohorts Amikacin · Gentamicin Tobramycin · Vancomycin Each cohort enrolls Low / Medium / High concentration ranges spanning the analytical measurement range. MDP1 = first protocol-defined milestone deliverable.
Fig. 2 Wave structure across the 27-cohort matrix. The four Wave 1 cohorts (testosterone, aldosterone, cortisol, mycophenolic acid) achieved MDP1 by end-April 2026 with cortisol fully closed. Wave 2 opens the 12 anti-epileptic cohorts at additional sites with neurology-clinic access. Wave 3+ contains the remaining six immunosuppressant / oncology cohorts, the antifungal cohort, and the four antibiotic cohorts — all sequenced per the analyte plan. Source: protocol cohort table (27 cohorts × 3 concentration ranges, 5 therapeutic categories); 30 April 2026 sponsor project update.

5. Discussion

Three observations bear noting. First, multi-analyte specimen-bank protocols for mass-spectrometry assay validation are operationally a 2-axis problem: analyte (27 cohorts) and concentration range (Low / Medium / High). The unit of work is the cohort × range slot at a defined clinical signature, not the patient or the analyte. The binding constraint is concentration-range coverage across the analytical measurement range, not total enrollment count. A program that enrolls 2,000 subjects all at the Medium range and zero at the Low and High ranges fails the protocol’s purpose; one that enrolls 25 well-distributed subjects per slot delivers the validation utility.

Second, holiday-window IRB pursuit is not the same operational problem as standard-window IRB pursuit. The 21-day end-to-end review for this protocol includes the U.S. late-December and early-January days when central IRB throughput is lower; the same review running across a non-holiday window would have closed in 7–15 days. Filing on 24 December rather than waiting until early January traded ~3 weeks of calendar time for ~2 weeks of effective review time and accelerated site activation by approximately three weeks.

Third, the wave-based therapeutic-category sequencing matters because the five categories pull from different patient populations. The Wave 1 hormones-plus-MPA combination was selected because endocrinology and transplant clinic populations are accessible at overlapping lead sites. Wave 2 anti-epileptics requires neurology-clinic access, motivating the activation of three new sites. Wave 3+ (additional immunosuppressants, antifungals, antibiotics) will pull from transplant, infectious disease, and inpatient / ICU populations, requiring further site-network extension. The site network is built around the cohort matrix, not the other way around.

6. Conclusion

Multi-analyte mass-spectrometry specimen-bank protocols are operationally distinct from longitudinal therapeutic-drug monitoring or single-analyte stability programs. A 27-cohort × 3-concentration-range matrix authorises 81 nominal sub-cohort slots and a 2,000-subject cap over a 24-month window; the binding constraint is range coverage, not enrollment count. A five-site lead network with wave-based therapeutic-category sequencing delivered 102 subjects in 90 days through a holiday-IRB window, achieved MDP1 on the four Wave 1 cohorts (with cortisol fully closed), and is positioned to absorb Wave 2 anti-epileptics across three additional sites. Wave 3+ cohorts — the remaining immunosuppressants and oncology agents, the antifungal cohort, and the four antibiotic cohorts — are sequenced per the sponsor analyte plan against the same matrix.