The International Prognostic Index for Chronic Lymphocytic Leukemia (CLL-IPI) is a tool designed to evaluate a patient's risk profile based on several clinical parameters. This risk assessment is done by calculating a total score from a set of patient data inputs and subsequently interpreting this score to project the patient’s 5-year survival probability.

To compute the risk score, the following patient characteristics are assessed:

- Age: 
  - Patients aged 65 years or younger receive a score of 0.
  - If a patient is older than 65 years, they receive a score of 1.

- Clinical Stage: 
  - A clinical stage of Binet A or Rai 0 scores 0.
  - A clinical stage of Binet B-C or Rai I-IV scores 1.

- Serum β2 Microglobulin Level (mg/L): 
  - Levels at or below 3.5 mg/L are scored as 0.
  - Levels above 3.5 mg/L receive a score of 2.

- IGHV Mutational Status:
  - Mutated IGHV is given a score of 0.
  - Unmutated IGHV is given a score of 2.

- TP53 Status:
  - If there are no abnormalities, the score is 0.
  - If there is a deletion 17p (detected via FISH) and/or a TP53 mutation (detected via sequencing), the score is 4.

Each characteristic contributes to a total risk score by adding up the specified scores for the categories that apply to the patient's data. The resulting score places the patient into one of four risk groups, providing crucial prognostic information:

- A total score of 0-1 indicates a low-risk group. Patients in this category have a projected 5-year survival rate of 93.2%.
- A total score of 2-3 indicates an intermediate-risk group, with a 5-year survival rate of 79.3%.
- A total score of 4-6 suggests a high-risk group, forecasting a 63.3% 5-year survival rate.
- A total score of 7-10 places the patient in a very high-risk group, with a significantly lower 5-year survival rate of 23.3%.

This risk assessment offers patients and healthcare providers valuable insights into patient prognosis based on specific clinical and genetic factors of chronic lymphocytic leukemia.

The calculator in question is the International Prognostic Index for Chronic Lymphocytic Leukemia, abbreviated as CLL-IPI. This scoring system is specifically designed for patients diagnosed with Chronic Lymphocytic Leukemia (CLL). The CLL-IPI is used to predict the prognosis of CLL patients, helping clinicians to stratify patients into different risk groups and guide treatment decisions. 

The CLL-IPI incorporates five variables: age, clinical stage, TP53 status, IGHV mutational status, and serum beta-2 microglobulin level. Each of these variables is assigned a score, and the total score determines the risk category (low, intermediate, high, or very high risk).

There are no specific exclusion criteria for the use of the CLL-IPI. However, it may not be as accurate in patients with rare or unusual presentations of CLL, or in patients with insufficient data to calculate all five variables.