diff --git a/src/pipeline.rs b/src/pipeline.rs
index b72ec93..17c9fc2 100644
--- a/src/pipeline.rs
+++ b/src/pipeline.rs
@@ -13,6 +13,7 @@ pub struct Pipeline {
     pub meta: HashMap<String, IcdMeta>,
     pub lexical: LexicalIndex,
     pub pool_size: usize,
+    pub valid_by_code: HashMap<String, bool>,
 }
 
 impl Pipeline {
@@ -20,7 +21,17 @@ impl Pipeline {
         let entries = corpus::load(&cfg.alpha_id_path)?;
         let meta = claml::load(&cfg.claml_path)?;
         let lexical = LexicalIndex::build_in_ram(&entries)?;
-        Ok(Self { entries, meta, lexical, pool_size: cfg.pool_size })
+        let valid_by_code = {
+            let mut m: HashMap<String, bool> = HashMap::new();
+            for e in &entries {
+                if let Some(code) = corpus::primary_code(e) {
+                    let v = m.entry(code.to_string()).or_insert(false);
+                    *v = *v || e.valid;
+                }
+            }
+            m
+        };
+        Ok(Self { entries, meta, lexical, pool_size: cfg.pool_size, valid_by_code })
     }
 
     /// Look up ICD metadata: exact code first, then — only for 6-char dotted codes
@@ -48,8 +59,8 @@ impl Pipeline {
                 && bytes[1].is_ascii_digit()
                 && bytes[2].is_ascii_digit()
                 && bytes[3] == b'.'
-                && bytes[4].is_ascii_alphanumeric()
-                && bytes[5].is_ascii_alphanumeric()
+                && bytes[4].is_ascii_digit()
+                && bytes[5].is_ascii_digit()
             {
                 if let Some(m) = self.meta.get(&code[..5]) {
                     return Some(m);
@@ -61,7 +72,7 @@ impl Pipeline {
 
     fn to_suggestion(&self, code: &str, phrase: &str, score: f32,
                      segs: Vec<usize>, alpha_valid: bool) -> Option<Suggestion> {
-        let m = self.meta_lookup(code)?;
+        let m = self.meta_lookup(code)?; // None ≈ 31 codes absent from ClaML entirely; accepted gap (see meta_lookup doc)
         Some(Suggestion {
             icd_code: code.to_string(),
             description: m.description.clone(),
@@ -95,23 +106,10 @@ impl Pipeline {
             }
         }
 
-        let valid_by_code: HashMap<String, bool> = {
-            let mut m = HashMap::new();
-            for c in &candidates {
-                m.entry(c.icd_code.clone()).or_insert(false);
-            }
-            for e in &self.entries {
-                if let Some(code) = corpus::primary_code(e) {
-                    if let Some(v) = m.get_mut(code) { *v = *v || e.valid; }
-                }
-            }
-            m
-        };
-
         let merged = cross_segment_dedupe(candidates);
         let mut suggestions = Vec::new();
         for (d, score) in merged {
-            let alpha_valid = *valid_by_code.get(&d.icd_code).unwrap_or(&false);
+            let alpha_valid = self.valid_by_code.get(&d.icd_code).copied().unwrap_or(false);
             if let Some(s) = self.to_suggestion(&d.icd_code, &d.best_phrase, score,
                                                 d.source_segments.clone(), alpha_valid) {
                 if filter.accepts(&s.tags) {