The Modified Marsh classification is a tool used to categorize the histological findings in celiac disease. It relies on a combination of three specific criteria: the number of intraepithelial lymphocytes per 100 enterocytes in the jejunum/duodenum, the morphology of crypts, and the condition of the villi. Each of these criteria has specific options that guide the classification into different Marsh types, which reflect varying degrees of intestinal damage.

The input criteria are as follows:

1. Intraepithelial lymphocytes per 100 enterocytes in the jejunum/duodenum:
   - Less than 40
   - Greater than 40

2. Crypt morphology:
   - Normal
   - Hypertrophic

3. Villi condition:
   - Normal
   - Mild atrophic
   - Marked atrophic
   - Absent

Based on the combination of these inputs, the classification into Marsh types is determined as:

- Type 0 is identified when there are fewer than 40 intraepithelial lymphocytes, with both crypts and villi being normal. This indicates no significant intestinal damage.

- Type 1 occurs with more than 40 intraepithelial lymphocytes, while crypts and villi remain normal. It suggests an early-stage celiac disease without visible structural damage to the crypts or villi.

- Type 2 comes into play with more than 40 intraepithelial lymphocytes, hypertrophic crypts, and normal villi. This reflects moderate histological changes with crypt hyperplasia but intact villi. 

- Type 3 is further subdivided based on the level of villous atrophy:
  - Type 3a: More than 40 intraepithelial lymphocytes, hypertrophic crypts, and mild villous atrophy. It signifies more severe damage compared to Type 2.
  - Type 3b: More than 40 intraepithelial lymphocytes, hypertrophic crypts, and marked villous atrophy. This indicates significant intestinal damage with advanced atrophic changes.
  - Type 3c: More than 40 intraepithelial lymphocytes, hypertrophic crypts, and absent villi. This type represents the most severe form of damage, with complete villous atrophy.

Each Marsh type reflects a distinct level of mucosal change, and this classification assists clinicians in assessing the severity and progression of celiac disease through microscopic evaluation of intestinal biopsy samples.

The Modified Marsh Classification is a diagnostic tool used specifically for the histologic findings in patients with suspected celiac disease. This classification system is based on the microscopic examination of small intestinal biopsy specimens. It categorizes the severity of the disease into seven stages (0-3c) based on the degree of intraepithelial lymphocytosis, crypt hyperplasia, and villous atrophy. 

The clinical utility of the Modified Marsh Classification is to provide a standardized method for diagnosing celiac disease and assessing the severity of the condition. It helps clinicians to determine the appropriate treatment plan and monitor the patient's response to a gluten-free diet. 

There are no specific exclusion criteria for the use of the Modified Marsh Classification. However, it should be noted that this classification system is only applicable to patients who have undergone a small intestinal biopsy, which is typically performed when celiac disease is suspected based on clinical symptoms and serological testing.

Modified Marsh classification of histologic findings in celiac disease