Abdominal transplant surgery certification through the Transplant Accreditation and Certification Council is examined orally, in two sessions assessed by two examiners each: one covering general and organ-specific transplant knowledge, the other discussing cases you submitted yourself. Practise with kidney, liver, pancreas and donation questions, and rehearse the viva in the Exam Simulator until you can defend your own cases out loud.
Content reviewed 26 August 2026 against current guidelines.
Start practising freeTaken from the bank, not written for this page. Answer it in your head, then open the explanation.
A 66-year-old male with ESRD due to hypertensive nephrosclerosis undergoes deceased-donor renal transplantation. Induction therapy is with basiliximab (non-depleting IL-2R antagonist). Maintenance immunosuppression: tacrolimus, MMF, prednisolone. On post-operative day 7, creatinine rises acutely from 189 to 312 µmol/L over 24 hours. Urine output drops from 1,800 mL to 620 mL in 24 hours. Tacrolimus trough is 11.4 ng/mL. Temperature is 37.2°C. BP is 158/92 mmHg. Doppler ultrasound of the transplant: RI 0.82 (elevated, normal <0.80) with slightly dampened systolic waveforms; no perirenal collection; no hydronephrosis. Urine microscopy: red cell casts 2+, granular casts 2+. A transplant kidney biopsy is performed. Which biopsy finding would be MOST consistent with acute calcineurin inhibitor (CNI) nephrotoxicity rather than acute T-cell-mediated rejection (Banff IA)?
Correct answer: A
This patient has an elevated tacrolimus trough (11.4 ng/mL — supratherapeutic; target typically 8–10 ng/mL at 1 week) in conjunction with acute deterioration of graft function. While acute TCMR and CNI nephrotoxicity can co-exist, the question asks for the biopsy finding MOST consistent with CNI nephrotoxicity. **Histological features of acute CNI nephrotoxicity:** 1. **Isometric vacuolisation of proximal tubular epithelial cells:** Fine, uniform-sized vacuoles throughout tubular cells (cytoplasmic) — direct mitochondrial toxicity from CNI. This is the most SPECIFIC histological marker of acute CNI nephrotoxicity. It may be focal or diffuse. 2. **Minimal or absent interstitial infiltrate:** CNI nephrotoxicity is primarily a tubular toxicity — the inflammatory component (interstitial infiltrate and tubulitis) is minimal or absent. This contrasts sharply with TCMR. 3. **Arteriolar vasoconstriction:** The affected arterioles appear narrowed with thickened walls, but without the intimal arteritis or endotheliitis of vascular rejection. 4. **Minimal tubulitis (t0-t1):** In CNI toxicity, tubulitis if present is minimal and not in non-atrophic tubules. In TCMR Banff IA, tubulitis is ≥2 in non-atrophic tubules. **Banff criteria for TCMR (discriminating features):** - **Banff IA:** Interstitial infiltrate i ≥2 (>25% of non-scarred cortex) + tubulitis t ≥2 in non-atrophic tubules - **Banff IB:** i ≥2 + t ≥3 - **Banff IIA:** i ≥2 + v1 (endarteritis, intimal arteritis) - **Banff IIB:** i ≥2 + v2 (severe endarteritis ≥25% luminal occlusion) - **Banff III:** Transmural arteritis/fibrinoid necrosis (v3) Options A (i2 + t2), C (v1), and D (v2) are all Banff criteria for TCMR. Option D (C4d in PTC) is a criterion for antibody-mediated rejection. Option A (isometric vacuolisation + minimal infiltrate) = CNI nephrotoxicity. **Management:** If CNI toxicity confirmed on biopsy — reduce tacrolimus dose to target trough 6–8 ng/mL; consider temporary switch to steroid-based bridge while IS is adjusted; avoid other nephrotoxins.
Teaching point. Acute CNI nephrotoxicity on biopsy: isometric vacuolisation of proximal tubular cells + minimal interstitial infiltrate + minimal tubulitis (t0-1); TCMR requires i ≥2 + t ≥2 in non-atrophic tubules; supratherapeutic trough (>10 ng/mL) supports CNI toxicity.
Referenced to Solez et al. Am J Transplant 2008 (Banff classification); Nankivell et al. NEJM 2003 (CNI nephrotoxicity landmark); Haas et al. Am J Transplant 2018 (Banff 2017)
Every question is explained like this — start with 50 free ›Every question is written by Pablo Lozano Lominchar, MD, PhD, and mapped to this board’s published syllabus. Before it enters the bank it has to pass an automated check: five options, a written explanation, and a citation — a named society guideline or a named trial. Benign and functional topics cannot be published without a society guideline; oncological ones cite NCCN, ESMO or AJCC, and the classification systems that govern a topic — Bethesda, TIRADS, Atlanta, Prague, Chicago — have to appear where they apply. The author has audited the full active bank against current guideline versions: what fails is re-cited, rewritten or withdrawn. 650 questions are currently withdrawn and are served to nobody.
Scope of authorship. ASTS/TACC sits outside the author’s own subspecialty practice, which is surgical oncology — peritoneal malignancy, sarcoma, hepatopancreatobiliary and complex pelvic surgery. No diplomate of this board has signed these questions off. What they offer is traceability rather than personal authority: every answer names the current guideline or trial it rests on, so you can check it at the source before you trust it. Found an error? Tell us — it gets corrected or withdrawn.
By oral examination in two sessions, each assessed by two examiners. One session covers general transplant knowledge and organ-specific topics; the other discusses cases submitted by the candidate in the certification application. It is offered twice a year, in the autumn and the spring.
The Fellowship Certification Pathway is for surgeons who completed a TACC-accredited abdominal transplant surgery fellowship from 2019 onwards. The Career Certification Pathway is for those who completed an ASTS or TACC accredited fellowship between 1998 and 2018 and whose primary surgical career is in abdominal transplant surgery. Both require an active, unrestricted licence and a case log.
No less than twenty-four months, of which at least eighteen must be clinical training; the remaining six may be clinical or research-based. Candidates must have completed a surgical residency satisfying the requirements for certification by a recognised American board or its foreign equivalent.
Rehearse out loud, including your own submitted cases, because the second session is a defence of your personal practice. The SurgBoardsQ&A Exam Simulator runs a two-station transplant viva by module — kidney, liver, pancreas or retrieval — presenting cases step by step and following up whenever your reasoning is incomplete.
SurgBoardsQ&A provides 1,549 transplant practice questions covering kidney, liver and pancreas transplantation, donation and retrieval, immunosuppression and rejection, each with a full guideline-referenced explanation.
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