MIPI: Keep WBC Units, the LDH Reference and Model Version Together

Quick Medical Calculator · Reading label 6 October 2026 · 4 min read

Retrospective study sequence, not publication date

A white cell count of 8.4 and one of 8,400 may describe the same blood sample. In a logarithmic prognostic model, entering the wrong representation changes the answer even though the displayed number looks plausible. The useful pre-calculation question is therefore not simply whether all boxes have a value. It is whether each value has the meaning required by this particular model.

First Name the MIPI Version

The original Mantle Cell Lymphoma International Prognostic Index was developed using 455 people with advanced-stage mantle cell lymphoma treated in three clinical trials. It combined age, performance status, LDH and white cell count to describe overall-survival prognosis. It was not a diagnostic test for lymphoma. Hoster and colleagues.

The QMC MIPI calculator uses the original continuous equation. It does not implement simplified MIPI or MIPI-C. The British Society for Haematology guideline distinguishes these versions and their inputs; a result generated under one must not inherit another version's label. The original continuous implementation does not take a Ki-67 value. BSH mantle cell lymphoma guideline, prognostication section.

Fictional Input Audit

This is an arithmetic exercise, not a treatment scenario. Assume an eligible specialist-assessed baseline record contains age 63 years, an independently established ECOG grade of 1, LDH 300 U/L with that laboratory's upper reference limit 240 U/L, and WBC 8.4 x 10^9/L.

Before entering anything, retain the original laboratory report and make the conversion explicit:

• WBC: 8.4 x 1,000 = 8,400 cells per microlitre.
• LDH normalisation: 300 / 240 = 1.25.
• Model: original continuous MIPI, with base-10 logarithms.

Independent calculation with those assumptions gives 6.0456. Executing the local calculation core with the same values gives the same result. This is a narrow arithmetic check, not a clinical validation or proof of the deployed website's behaviour. The number is an index, not 6.0456% survival or a probability of response.

Independent arithmetic using 8.4 where the equation requires 8,400 gives 3.2277. The difference is 2.8179 index units. This wrong-unit example was calculated separately, not tested through the displayed calculator. The error can substantially change the apparent prognostic classification; it does not represent improvement in the disease. Both outputs come from the same fictional observation, but only one respects the input convention.

Preserve the Denominator

An LDH concentration is incomplete for this model without the appropriate laboratory upper limit. Do not borrow a reference value from a different report, a different assay or an old note merely to make the form calculate. In the example, 300 and 240 share the same unit, so their ratio has no unit. Changing the numerator's unit without changing the denominator's unit destroys that comparison.

Record the laboratory, specimen time and reference limit together. If the upper limit is unavailable, leave the model incomplete while obtaining the source information. The checked local core rejected a blank upper limit; that software safeguard cannot detect an upper limit that is present but belongs to the wrong laboratory.

The performance-status input likewise requires an actual assessment. It is not a quantity that can be inferred from age, averaged between clinicians or converted automatically from another scale. A completed numerical field does not establish that the underlying observation was valid.

A Reusable Handover Note

An original input-provenance note can use five short lines: diagnosis and intended baseline; named model version; WBC as reported and as entered; LDH with its matched upper limit; and source of the performance assessment. Finish with any unresolved measurement or timing issue. Keep the unrounded calculation available, while presenting a sensible number of decimal places.

For this example, a useful concluding sentence is: "Original continuous MIPI calculated from the stated baseline data; WBC converted from 8.4 x 10^9/L to 8,400 cells per microlitre; LDH ratio 1.25." It communicates more than an isolated risk label and allows another clinician to reproduce the input handling.

What the Check Does Not Decide

Correct units establish only one part of correctness. The selected patient must still match the model's intended context, and historical prognostic performance need not transfer unchanged to different populations or treatment eras. Do not select treatment, assign an individual survival percentage or replace specialist assessment with this result. An accurate calculation is useful precisely when its limits remain attached to it.

Retrospective educational reading plan: Day 32 of 50, labelled 2026-10-06. This is a study-sequence label, not a historical publication or clinical-review date. The publication date above records the actual release.