Active or latent infection requiring resolution / prophylaxis before initiating long-dura...

Deterministic view of the source YAML entity. Clinical authority remains with the cited source IDs and reviewer sign-off state.

ID	`RF-MTC-INFECTION-SCREENING`
Type	Red flag
Status	reviewed 2026-04-27 \| pending_clinical_signoff
Diseases	`DIS-MTC`
Sources	`SRC-ATA-THYROID-2015` `SRC-NCCN-THYROID-2025`

Red Flag Origin

Definition	Active or latent infection requiring resolution / prophylaxis before initiating long-duration RET-targeted (selpercatinib / pralsetinib) or multikinase (vandetanib / cabozantinib) therapy in MTC: HBsAg-positive (HBV reactivation reported on TKI-class), anti-HBc-positive (occult HBV — chronic TKI exposure raises reactivation), HIV-positive (ART coordination, CYP3A4 interactions with TKIs), or active TB.
Clinical direction	hold
Category	infection-screening

Trigger Logic

{
  "any_of": [
    {
      "finding": "hbsag",
      "value": "positive"
    },
    {
      "finding": "anti_hbc_total",
      "value": "positive"
    },
    {
      "finding": "hiv_status",
      "value": "positive"
    },
    {
      "finding": "active_tb",
      "value": true
    }
  ],
  "type": "lab_value"
}

Notes

RET-targeted therapy is typically multi-year (median PFS >25 mo on selpercatinib in LIBRETTO-001) — chronic exposure raises HBV reactivation risk meaningfully even in HBsAg-negative / anti-HBc+ patients. Standard practice: HBsAg + anti-HBc + anti-HBs serology pre- TKI; entecavir / tenofovir for HBsAg+. HIV+: selpercatinib / pralsetinib / cabozantinib are CYP3A4 substrates — coordinate ART to avoid CYP3A4 inhibitors (ritonavir-boosted PIs) which raise TKI exposure 2-3 fold. Active TB: rifampin (CYP3A4 inducer) lowers TKI exposure significantly — prefer rifabutin if anti-TB needed.

Used By

No reverse references found in the YAML corpus.