Chicago Classification (Achalasia Subtype)
Assigns the manometric subtype of achalasia (Chicago Classification v4.0).
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Abnormal median IRP
- Yes
- 100% absent peristalsis
- Yes
- Pressurization >= 20%
- Yes
Result: Achalasia type II - panesophageal pressurization in 20% or more of swallows, with no spasm.
The tool opens with these values already filled in. Replace them with your own.
What the result means
- Required
- Both an abnormal median integrated relaxation pressure AND 100% absent peristalsis. Neither is optional, and the body findings mean nothing without them.
- Type III
- 20% or more premature or spastic swallows: distal latency under 4.5 s with a distal contractile integral above 450.
- Type II
- Panesophageal pressurization in 20% or more of swallows, without spasm.
- Type I
- Failed peristalsis with neither pressurization nor spasm.
- Why it matters
- The subtype separates who tends to do well with pneumatic dilation from who is usually offered a myotomy; type II generally has the best outcomes.
What you enter
- Abnormal median IRP
- 100% absent peristalsis
- Premature swallows >= 20%
- Pressurization >= 20%
How this is calculated
Yadlapati R, Kahrilas PJ, Fox MR, et al. Esophageal motility disorders on high-resolution manometry: Chicago classification version 4.0. Neurogastroenterol Motil. 2021;33(1):e14058. Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.