Readout Interpretation Guide

Every score the platform displays — range, biological meaning, calculation, failure modes, reliability, ranking usage, worked example.

Structural confidence

ipTMiptm
Range
[0, 1]; higher means greater model confidence in the generated chain arrangement; no binding cutoff
Meaning
Interface predicted TM-score. It describes model confidence in the relative chain arrangement of a generated pose, not binding probability, affinity, or specificity.
Calculation
Output of AlphaFold-Multimer / Boltz-2 / Protenix, aggregated from predicted inter-chain positional-error information into one model-confidence score.
Failure modes
A non-binder or incorrect biological pairing can still receive high ipTM, while a real binder can receive a low score. Construct boundaries, model version, and seed can change the result.
Reliability
Useful for same-protocol pose triage. Multi-model or multi-seed agreement can expose sensitivity but cannot prove that an agreed pose is biologically correct.
Use for ranking
Rank generated-pose confidence only under the same protocol. Do not rank binding, affinity, specificity, or candidate advancement from ipTM alone; require orthogonal experiments.
Example: ranking two candidates
Candidate A ipTM 0.85 and B 0.72 means A received higher pose confidence from this model run. It does not mean A binds more tightly—or at all.
ensemble_iptmensemble_iptm
Range
[0, 1]
Meaning
Arithmetic mean of Boltz-2 and Protenix ipTM. It summarizes model-reported pose confidence, not binding probability.
Calculation
mean(boltz_iptm, protenix_iptm). Future versions will weight by per-model reliability.
Failure modes
Averaging can hide disagreement, and correlated models can agree on an incorrect or non-binding pose.
Reliability
A pose-triage summary only. Pair with explicit model/seed agreement and inspect structures; require experiments for biological claims.
Use for ranking
Use only to compare pose confidence under a fixed protocol, not to rank affinity, specificity, or probability of binding.
Example: ranking two candidates
Boltz ipTM 0.80 and Protenix 0.78 gives ensemble 0.79. This records similar confidence scores; it does not validate the interface or binder.
ensemble_agreementensemble_agreement
Range
[0, 1] when reported; interpretation requires a versioned method
Meaning
A model-to-model agreement feature. Scalar ipTM similarity, contact-set overlap, and coordinate convergence are different definitions and must not be mixed.
Calculation
Read the stored method/version with the value. If provenance is absent, treat the number as legacy/undefined rather than assuming an ipTM-difference or Jaccard formula.
Failure modes
Models can share a failure, and similar scalar confidence does not imply similar coordinates. Low agreement does not reveal which model is closer to reality.
Reliability
Useful for flagging model sensitivity, not as evidence of binding or correctness.
Use for ranking
Use as a manual-review flag alongside coordinate/contact convergence. Do not automatically drop or advance candidates from this scalar.
Example: ranking two candidates
Agreement 0.9 is interpretable only with its method: scalar-score similarity and contact-set overlap are not interchangeable, and neither proves binding.
pLDDTplddt
Range
[0, 100]; <50 disordered; 50-70 low; 70-90 confident; >90 very high
Meaning
Per-residue confidence in atomic positions. AlphaFold's own granular signal.
Calculation
Model output, distilled from training-set positional accuracy.
Failure modes
Mean pLDDT masks region-specific issues. CDR-H3 natively 60-80 is normal; framework at 70 indicates structural problems. Doesn't capture rigidity vs flexibility.
Reliability
Well-validated against PDB. For antibody framework, expect >90 as baseline; <80 is a red flag.
Use for ranking
Report per-region (FR / CDR-H1/H2/H3 / LCDR) when possible. Mean pLDDT alone is a weak signal for antibodies.
Example: ranking two candidates
A mean pLDDT 75 (FR 92, HCDR3 58) → fine, HCDR3 variability is expected. B mean pLDDT 75 (FR 70, HCDR3 80) → suspicious framework.

Interface quality

iPAE (interface PAE)ipae
Range
[0, 30+] Å; lower means the model reports less inter-chain positional uncertainty
Meaning
Predicted aligned error over selected inter-chain pairs. It describes uncertainty in generated geometry, not whether the molecules bind.
Calculation
AlphaFold / Boltz output. Mean PAE over inter-chain residue pairs at the interface.
Failure modes
A low value can occur for a confident but biologically incorrect pose. The selected interface mask and model version affect the summary.
Reliability
Use with ipTM, model/seed convergence, and structure inspection as pose-confidence diagnostics; none establishes binding.
Use for ranking
Lower can prioritize poses for review under the same protocol. There is no validated iPAE threshold for real binding or specificity.
Example: ranking two candidates
A iPAE 4 Å and B 12 Å means the model reports less positional uncertainty for A's selected inter-chain pairs; it does not prove A binds.
p_bindp_bind
Range
[0, 1]; raw RF2 classifier output, not a calibrated binding probability
Meaning
An interaction-classifier score emitted by RF2. It is an exploratory model feature, not an answer to whether a binder will bind an antigen.
Calculation
Classifier head on RF2 features, returning one scalar per modeled pair.
Failure modes
Dataset shift and calibration error can produce high scores for non-binders and low scores for binders; the value is not K_D or specificity.
Reliability
Use only as a same-protocol review feature and retain model/version provenance.
Use for ranking
Do not use a universal threshold or advance candidates from p_bind alone. Require orthogonal binding and specificity experiments.
Example: ranking two candidates
p_bind 0.92 means this RF2 head emitted a high score. It is not a 92% chance of binding and does not replace SPR/BLI or functional assays.
BSA (buried surface area)bsa_total / bsa_antibody / bsa_antigen
Range
Ų; the current Interface report uses partner-averaged buried area
Meaning
Surface area occluded at the interface in the predicted pose. It describes modeled geometry, not whether binding occurs or how tight it is.
Calculation
Shrake-Rupley SASA: reported BSA = [SASA(Ab alone) + SASA(Ag alone) - SASA(complex)] / 2. Per-partner buried areas may also be reported.
Failure modes
A wrong or experimentally non-binding pose can still have a large BSA. BSA alone does not establish affinity, specificity, or promiscuity.
Reliability
Use as a pose-geometry diagnostic alongside PAE/ipTM, model or seed agreement, and contact inspection; experimental calibration is required for biological claims.
Use for ranking
Do not rank affinity from BSA alone. Compare values only under the same prediction and SASA protocol, then inspect the modeled interface.
Example: ranking two candidates
A BSA of 1200 Ų means the predicted pose has a broad occluded interface. A value of 1900 Ų plus high hydrophobicity is a review flag, not proof of a sticky non-specific binder.

Antibody-likeness

AbLang perplexityablang_perplexity_vh / ablang_perplexity_vl / ablang_avg
Range
Lower = more antibody-like; typical 2-6 for human repertoire sequences
Meaning
How surprised an antibody language model is by your sequence. Low perplexity = looks like a natural human antibody.
Calculation
AbLang model forward pass; perplexity is exp(mean negative log-likelihood) over the sequence.
Failure modes
Designed sequences may be 'too natural' (memorizing repertoire) or unusually low for de novo binders — interpret in context.
Reliability
Strong prior for expressibility. Sequences with perplexity above the repertoire distribution are higher risk of expression failure.
Use for ranking
Use as a developability prior. Heavy chain (VH) perplexity carries more weight than light (VL) for VHH and scFv.
Example: ranking two candidates
A ablang_avg 3.1 (in repertoire distribution) → likely expressible. B ablang_avg 12 → outside distribution, expression risk.

Developability (TAP)

TAP (Therapeutic Antibody Profiler)tap_psh / tap_ppc / tap_pnc / tap_sfvcsp / tap_flags / tap_cdr_length
Range
Per-metric — TAP returns continuous values plus PASS/AMBER/RED flags
Meaning
Five canonical developability filters: total CDR length, patches of surface hydrophobicity (PSH), patches of positive charge (PPC), patches of negative charge (PNC), structural Fv charge symmetry parameter (SFvCSP). Hardcoded gates derived from clinical-stage antibody distributions.
Calculation
TAP 2.0; structural analysis of Fv with patch detection. Compares against the clinical-stage antibody (CST) distribution.
Failure modes
Calibrated on traditional mAbs; VHH and engineered scFv distributions differ. Some 'red' flags are false positives for unconventional formats.
Reliability
Industry-standard for IgG developability assessment. Take 'red' flags seriously; investigate per-flag rationale.
Use for ranking
Use as hard gates: any TAP RED flag → drop unless rescued. For mAb format, all five metrics in CST range = developable.
Example: ranking two candidates
A all TAP flags GREEN → developable. B PSH RED, PPC RED → likely will aggregate / non-specific binding; deprioritize.

Stability

ThermoMPNN ΔΔGthermompnn_ddg
Range
kcal/mol; negative = stabilizing; -2 to +2 typical range for designs
Meaning
Predicted stability change from mutations. Negative = the mutation stabilizes the fold.
Calculation
ThermoMPNN forward pass on each mutation site, comparing wt vs mutant energy.
Failure modes
Trained on monomer thermal denaturation data; less calibrated for interface stability or chronic-expression contexts.
Reliability
Strong directional signal but absolute ΔΔG values have ~1 kcal/mol error.
Use for ranking
For each candidate, compute mean predicted ΔΔG; prefer negative averages. Use as a tie-breaker after interface metrics.
Example: ranking two candidates
A mean ddG -1.2 → designed stabilizing mutations. B mean ddG +2.5 → fold is fragile.

Aggregation

AggreScan3Daggregation_score
Range
Continuous; lower = less aggregation propensity
Meaning
Structure-aware aggregation prediction. Identifies aggregation-prone patches on the folded structure.
Calculation
AggreScan3D rolls a hydrophobicity-weighted score along the molecular surface; reports aggregation hotspots.
Failure modes
Static structural — doesn't capture dynamic exposure of hydrophobic patches at higher temperature.
Reliability
Standard tool; correlates moderately with measured aggregation propensity.
Use for ranking
Lower is better. Pair with TAP PSH for a more complete aggregation picture.
Example: ranking two candidates
A aggregation_score 0.15 → smooth surface, low risk. B 0.65 + tap_psh RED → high aggregation risk; deprioritize.

Humanness / Immunogenicity

Humanness (BioPhi OASis)humanness
Range
[0, 1]; >0.85 native-human-like; <0.6 likely to elicit ADA
Meaning
How similar your sequence is to the natural human antibody repertoire.
Calculation
OASis: percentile-rank of 9-mer subsequences vs the Observed Antibody Space database.
Failure modes
Excellent for traditional mAbs; less validated for VHH (camelid origin). High humanness doesn't guarantee no ADA — clinical ADA is multifactorial.
Reliability
Industry standard. Strongly correlates with clinical immunogenicity for traditional antibodies.
Use for ranking
Higher is better. For VHH, supplement with cross-reactivity counter-screen against human Ig.
Example: ranking two candidates
A humanness 0.91 → low immunogenicity risk. B 0.55 → needs humanization or risk of ADA.
DeepImmuno (MHC-I)immunogenicity
Range
[0, 1]; lower = fewer MHC-I-binding epitopes
Meaning
Predicted T-cell epitope load. High = more MHC-I-presentable peptides → higher immunogenicity risk.
Calculation
DeepImmuno predictor over all 9-mer fragments of the binder.
Failure modes
Only covers MHC-I (CD8 response). Doesn't capture B-cell ADA or MHC-II / CD4 responses.
Reliability
Useful supplement to humanness; not a substitute for full immunogenicity panel.
Use for ranking
Lower is better. Combine with humanness to triage.
Example: ranking two candidates
A immunogenicity 0.08 + humanness 0.92 → low risk all-around. B immunogenicity 0.35 + humanness 0.95 → check whether MHC-I hits are in CDR vs framework.

CDR geometry

CDR geometry validationcdr_geometry_ok
Range
Boolean (pass / fail)
Meaning
ANARCI-based check that CDR lengths fall within canonical IMGT ranges.
Calculation
ANARCI numbering → extract CDR-H1/H2/H3 + L1/L2/L3 lengths → compare against IMGT canonical ranges.
Failure modes
Length-only check; doesn't validate loop conformation, just that the length is plausible.
Reliability
Hard gate — failures usually indicate the design has produced something that won't fold like an antibody.
Use for ranking
Boolean filter. Drop candidates with cdr_geometry_ok = false unless intentionally non-canonical.
Example: ranking two candidates
A all CDRs canonical → fine. B CDR-H3 of length 32 → flagged (typical HCDR3 is 5-25 aa); investigate.

Contact geometry

HCDR3 contact dispersionhcdr3_contacts / hcdr3_dispersion / hcdr3_contact_fraction
Range
Std-dev in residue positions; typical 1.5-4 for good binders
Meaning
How spread out the antigen-contacting residues are along HCDR3. Concentrated contacts can indicate a non-canonical paratope.
Calculation
ANARCI annotate → identify HCDR3 residues → find contacts (within 5 Å of antigen heavy atoms) → std-dev of contact positions.
Failure modes
5 Å threshold is arbitrary; doesn't distinguish productive contacts from incidental ones. Heavy-atom-only — ignores hydrogen-bond geometry.
Reliability
Useful sanity check; not a primary ranker.
Use for ranking
Prefer 1.5-4. Very low (<1) means contacts cluster on one or two residues (possibly non-canonical). Very high (>4) means HCDR3 is so long the spread is meaningless.
Example: ranking two candidates
A HCDR3 length 14, contacts 8, dispersion 3.1 → reasonable contact distribution. B HCDR3 length 14, contacts 3, dispersion 0.5 → all contacts on one residue, suspicious.

Glycosylation

N-glycosylation sitesglyco_sites_count / glyco_sites_positions / glyco_sites_in_cdr_count
Range
Count of motif matches; 0 = clean; >0 in CDR = red flag
Meaning
N-glyco motif N-X-S/T (X != P). In CDR = developability red flag for mAb format (affects PK, aggregation).
Calculation
Regex motif scan or Tamarind n-linked-glycosylation tool. CDR overlap computed via ANARCI numbering.
Failure modes
Motif scan flags potential, not confirmed glycosylation. Actual glycosylation depends on cell line and local context.
Reliability
Conservative — flags more than actually glycosylate. Treat CDR hits as hard fails for mAb format; framework hits as soft warnings.
Use for ranking
0 in CDR = preferred. Any CDR hit for mAb format = drop unless intentional.
Example: ranking two candidates
A glyco_sites_count 2, glyco_sites_in_cdr_count 0 → fine, framework hits are tolerable. B glyco_sites_in_cdr_count 1 → drop for mAb.

PK proxy

MW (kDa) + pImw_kda / pi
Range
MW: mAb ~150 kDa, scFv ~25, VHH ~13. pI: 6-9 typical; <6 or >9 = formulation challenges
Meaning
Molecular weight (kDa) and isoelectric point (pI). Basic format-fit + PK proxy.
Calculation
BioPython ProtParam — exact MW from residue composition; pI from titration curve.
Failure modes
Doesn't capture glycosylation effects on apparent MW. pI doesn't tell you about local charge distribution (use TAP PPC/PNC for that).
Reliability
Exact computation; reliable. Limited interpretive power on its own.
Use for ranking
Use as a format-fit hard gate (e.g. for in-vivo CAR mRNA, total CAR construct ≤ 1.5 kb). pI in 6-9 range is preferred for manufacturability.
Example: ranking two candidates
A VHH MW 13.2 kDa, pI 7.8 → fits in mRNA-LNP, no formulation issues. B VHH MW 18 kDa, pI 4.5 → too large for CAR + acidic pI complicates formulation.
Fc–FcRn pose confidence (exploratory; not wired)fcrn_binding
Range
Planned Fc–FcRn complex ipTM; no validated affinity or half-life threshold
Meaning
Model confidence for a generated Fc–FcRn arrangement. It does not measure pH-dependent affinity, recycling, pharmacokinetics, or serum half-life.
Calculation
Planned Boltz-2 prediction of an Fc + FcRn complex; backend is not wired. A sequence-only structure prediction does not itself encode or validate endosomal pH behavior.
Failure modes
Even a confident pose may be non-binding or have the wrong pH dependence. Fc sequence, glycosylation, kinetics, exposure, and clearance all affect PK.
Reliability
Unvalidated against SPR/BLI or PK data. Treat only as a future structure-review feature.
Use for ranking
Do not rank half-life or choose Fc engineering from ipTM. Require pH-dependent FcRn binding assays and PK evidence.
Example: ranking two candidates
(Pending wiring) Fc–FcRn ipTM 0.92 would mean high model confidence in one generated pose—not long half-life.

Cross-species reactivity

Cross-species pose comparison (exploratory)xspecies_human_iptm / xspecies_cyno_iptm / xspecies_mouse_iptm / xspecies_retention
Range
Per-ortholog ipTM; ratio = cyno_iptm / human_iptm (or analogous); no validated cutoff
Meaning
Compares model confidence for generated poses against antigen orthologs. It does not determine cross-species binding or pharmacology-species suitability.
Calculation
Re-predict the complex with cyno / mouse antigen ortholog (from UniProt). Report per-species ipTM + retention ratio. Status: data file + runner pending.
Failure modes
Ortholog construct boundaries, model bias, and different generated poses can dominate the ratio. Similar scores can occur without shared binding, and dissimilar scores do not prove loss of binding.
Reliability
An uncalibrated model-review signal only. It cannot establish toxicology relevance or predict whether cyno/mouse PK mirrors human PK.
Use for ranking
Do not use the ratio as an IND gate. Confirm ortholog binding, kinetics, epitope conservation, function, and PK with appropriate experiments.
Example: ranking two candidates
human ipTM 0.85 and cyno 0.79 flags similar model confidence under one protocol; it does not prove cyno cross-reactivity or validate a cyno study.

Cross-reactivity

Counter-screen ΔipTM (exploratory pose delta)selectivity
Range
Δ ipTM = target_ipTM - max(homolog_ipTM); no validated specificity threshold
Meaning
Difference between target and homolog pose-confidence outputs under one modeling protocol. It is not measured selectivity or proof of target preference.
Calculation
Run the same model, constructs, seeds, and settings on (binder, target) and (binder, each homolog); report the ipTM gap. Example BCMA panel: TACI, BAFF-R.
Failure modes
Model/construct bias, incomplete off-target panels, and different pose modes can create or erase the gap. A confident off-target pose is not proof of cross-binding.
Reliability
Use as a manual-review flag only. Experimental selectivity and functional counter-screen panels are required.
Use for ranking
Do not apply a universal cutoff or automatically redesign/deprioritize from ΔipTM. Compare only under the same protocol and seek orthogonal evidence.
Example: ranking two candidates
Target ipTM 0.85 and TACI 0.45 gives ΔipTM 0.40: a model-triage difference to inspect, not a 'clean' specificity result.

CAR-T specific

tonic_clustering_risk (heuristic v0)tonic_clustering_risk
Range
[0, 1]; lower = safer; <0.3 acceptable, >0.6 high risk
Meaning
Composite proxy for binder-driven CAR clustering on T-cell surface without antigen present. Drives tonic signaling (T-cell exhaustion).
Calculation
Composite: surface hydrophobicity + net charge at pH 7.4 + Fv-Fv self-association. Heuristic, NOT validated against experimental data.
Failure modes
First-principles heuristic with no clinical or experimental calibration. Marked as 'v0' for a reason.
Reliability
Use as a soft warning only. Don't kill candidates on this score alone until calibrated against IASO internal data.
Use for ranking
Lower is better, but treat as a flag, not a hard filter.
Example: ranking two candidates
A tonic_clustering_risk 0.25 → green flag. B 0.7 + tap_psh high → would deprioritize but should validate experimentally.
CAR score (composite, heuristic)car_score (composite heuristic)
Range
[0, 1]; higher = more CAR-T-compatible (hand-tuned)
Meaning
Aggregate of size + stability + expression prediction + aggregation + immunogenicity for CAR-T format-fit.
Calculation
Hand-tuned weighted composite. Not learned, not calibrated against clinical CAR-T performance.
Failure modes
Public literature has no validated CAR-fit predictor. Our composite weights are best-guesses.
Reliability
Treat as 'heuristic v0'. Useful for quick triage; not a substitute for wet-lab CAR-T validation.
Use for ranking
Higher is better, but always check the underlying components separately.
Example: ranking two candidates
A car_score 0.85 → looks good on aggregate. But if A's tonic_clustering_risk is 0.7, the composite is misleading.

Composite + ranking

Pareto rankpareto_rank
Range
Positive integer; 1 = best (non-dominated), higher = dominated by some candidate
Meaning
Multi-objective rank: a candidate is Pareto rank 1 if no other candidate is better on every dimension simultaneously.
Calculation
Non-dominated sort across included model dimensions: pose confidence (ipTM), stability (ddG), humanness, developability, immunogenicity, and aggregation.
Failure modes
The frontier inherits every input limitation: ipTM is not binding or affinity evidence, and highly correlated dimensions can distort the frontier.
Reliability
Mathematically clean but UX-dangerous if interpreted as 'rank 1 = best candidate'.
Use for ranking
Use only for exploratory multi-model triage. Re-rank biological decisions with calibrated affinity and orthogonal experimental evidence—not ipTM alone.
Example: ranking two candidates
A rank 1, B rank 1, C rank 2 → A and B are both non-dominated relative to C. A vs B requires another tie-breaker.
Composite scorecomposite_score
Range
[0, 1]; higher = better overall
Meaning
Weighted linear combination of normalized score dimensions per scoring preset (permissive / standard / strict).
Calculation
Sum of weight_i × normalized(score_i). Default weights in scoring_stage.py DEFAULT_WEIGHTS.
Failure modes
Linear combination hides which dimension drove the score. Two candidates with same composite can be very different.
Reliability
Convenient single-number ranker but always drill into components before promoting a candidate.
Use for ranking
Higher is better. Use as the default sort on /candidates; always cross-reference Pareto rank + individual dimensions.
Example: ranking two candidates
A and B can both score 0.85 for different reasons. A's higher ipTM means higher modeled pose confidence, not stronger binding; inspect every component and experimental evidence.