What is the difference between WPSS and IPSS in MDS?

The original IPSS (International Prognostic Scoring System) can only be applied at the time of MDS diagnosis and uses blast percentage, karyotype, and cytopenias. WPSS uses WHO morphologic category instead of blasts, and replaces cytopenia count with transfusion dependency, allowing dynamic re-scoring at any point during the disease course.

How is transfusion dependency defined in WPSS?

A patient is considered transfusion dependent if they require at least one red blood cell transfusion every 8 weeks, assessed over a 4-month observation period. Occasional transfusions for acute events (e.g., surgery) do not qualify.

What karyotypes fall into each cytogenetic risk group?

Good: normal karyotype, isolated del(5q), isolated del(20q), or loss of Y chromosome (-Y). Poor: complex karyotype (3 or more abnormalities) or chromosome 7 abnormalities (monosomy 7 or del(7q)). Intermediate: all other abnormalities not classified as Good or Poor.

Can WPSS be used after treatment has started?

Yes. One of WPSS's key advantages is that it can be calculated at any time during the disease course, making it useful for serial risk reassessment as the disease evolves or responds to therapy.

How does WPSS relate to AML transformation risk?

Higher WPSS scores correlate with a greater cumulative probability of AML evolution. Very Low and Low risk groups have a low 5-year AML risk (~3–8%), while Very High risk approaches 70–80% at 5 years.

WPSS MDS Score Calculator

Select WHO MDS category, karyotype, and transfusion dependency to calculate the WPSS score and estimate risk group with median overall survival.

For educational use only. WPSS estimates are based on population-level data from the original derivation cohort. All results must be interpreted by a qualified hematologist or oncologist in the full clinical context. Not a substitute for clinical judgment.

WPSS Score — Risk Group Reference

Score	Risk Group	Median OS	~5-yr AML Risk
0	Very Low	136 months (~11.3 yrs)	~3%
1	Low	63 months (~5.3 yrs)	~8%
2	Intermediate	44 months (~3.7 yrs)	~20%
3–4	High	19 months (~1.6 yrs)	~45%
5–6	Very High	8 months (~0.7 yrs)	~70%

Source: Malcovati L et al., J Clin Oncol 2007. Median OS and AML risk estimates reflect the original derivation cohort and may differ in contemporary practice.

Summary

Select WHO MDS category, karyotype, and transfusion dependency to calculate the WPSS score and estimate risk group with median overall survival.

How it works

Select the WHO MDS sub-type that best fits the patient's bone marrow and blood findings.
Choose the cytogenetic risk group based on the karyotype from the bone marrow cytogenetic analysis.
Indicate whether the patient is transfusion dependent (requires at least 1 red cell unit every 8 weeks over a 4-month period).
Click Calculate to compute the total WPSS score (0–6).
Review the resulting risk group, estimated median overall survival, and 5-year AML evolution risk.

Use cases

Estimate prognosis at diagnosis or during follow-up in MDS patients.
Guide treatment decisions: watchful waiting vs. disease-modifying therapy vs. stem cell transplant.
Risk-stratify patients for clinical trial eligibility.
Counsel patients and families on expected disease course.
Serial assessment over time to detect disease progression.
Educate hematology trainees on MDS prognostic variables.

WPSS MDS Score Calculator

1 WHO MDS Category

2 Cytogenetic Risk Group (Karyotype)

3 Transfusion Dependency

WPSS Score

Score Components

Clinical Notes