Allred score calculator

Allred score calculator

The Allred score table

The Allred score was described for oestrogen and progesterone receptor staining in breast cancer. It adds two scores given to the tumour cell nuclei.

Allred total score = proportion score + intensity score (0, or 2 to 8)

Worked example: 40 % of tumour nuclei are positive, with intermediate staining on average. 40 % falls between one third and two thirds, so the proportion score is 4; intermediate intensity is 2; the total is 4 + 2 = 6.

Published tables print the band edges slightly differently (10 % appears under both 2 and 3). This calculator puts a value that sits exactly on an edge in the higher band: 1 % scores 2, 10 % scores 3, one third scores 4 and two thirds scores 5, which is also how QuPath and SlideScope compute it.

Published cut-offs, and what guidelines use now

• The original cut-off: in the 1998 description, a total score of 0 or 2 was read as negative and 3 to 8 as positive. A total of 3 needs at least 1 % of cells weakly stained.
• Current breast guidelines report percentages: the 2020 ASCO/CAP update for oestrogen and progesterone receptor testing reads 1 % to 100 % of tumour nuclei as positive, under 1 % as negative, and reports 1 % to 10 % as "ER Low Positive". Many reports give the percentage and intensity with or without an Allred or H-score.
• One intensity for the whole tumour: the intensity score is an average, so a mix of weak and strong cells becomes "intermediate". Use the H-score when the spread of intensities matters.
• Other markers: the score is sometimes borrowed for other nuclear markers in research. State that you did so and which cut-off you used.

Getting the same score from software

Image analysis software reaches these scores by the same arithmetic, with the eye replaced by a measurement. It finds every nucleus in the region, separates the brown DAB stain from the blue haematoxylin by colour deconvolution, measures the mean DAB optical density of each nucleus, and grades it against thresholds you set: one threshold for positive or negative, three for 1+, 2+ and 3+.

• QuPath (free, open source): Positive cell detection with one threshold gives percent positive; with three thresholds it also reports the H-score.
• Fiji / ImageJ (free): Colour Deconvolution with the H DAB vectors, then threshold and count; the scoring arithmetic is yours to do.
• SlideScope: counts nuclei in the region you choose, grades each one, and reports percent positive, H-score and Allred score together, using the same definitions as QuPath. You can also ask in plain language with Ask Your Slide; every number comes from the local tool, with outlines to check. Research use only.

Whichever you use, the thresholds are choices: write them in your methods, check the outlines against the image, and keep them fixed across the slides you compare. Step by step: how to quantify IHC staining.

Questions

Sources

• Allred DC, Harvey JM, Berardo M, Clark GM. Prognostic and predictive factors in breast cancer by immunohistochemical analysis. Mod Pathol 1998;11(2):155-168
• Allison KH et al. Estrogen and progesterone receptor testing in breast cancer: ASCO/CAP guideline update. Arch Pathol Lab Med 2020;144(5):545-563
• QuPath documentation: cell classification and intensity thresholds

These calculators do arithmetic for research and teaching. They are not a diagnostic tool: scoring for patient care follows the validated assay, the current guideline for that marker and a pathologist's judgement.