# Hematopathology Cell Counter

> Hematopathology Cell Counter (also called Cell Counter, at cellcounter.app) is a free manual differential counter for bone marrow aspirates and peripheral blood smears. It runs in the browser, keeps every count on the user's device, and produces reports with percentages, the M:E ratio and a separately counted nRBC section. It is a counting aid for hematopathologists and laboratory professionals; it does not diagnose, classify risk or recommend treatment.

Key facts:

- Web app: https://cellcounter.app/ (free, no account, no installation; requires JavaScript). Also built for iPhone, iPad and Android.
- Built-in templates: Bone Marrow Aspirate (20 cell types, 500-cell default target, M:E ratio), PBS Five-Part (100-cell default target) and PBS Extended / Immature Myeloid (100-cell default target). Users can build and share their own templates.
- Counting: tap a cell tile or press its keyboard shortcut; count up to or down from any target; undo and redo; quality-control checkpoints at count milestones.
- Calculations: percentage = cell count ÷ differential total × 100; M:E ratio = myeloid total ÷ erythroid total; nRBC per 100 WBC = nRBC count × 100 ÷ differential total; optional corrected WBC = uncorrected WBC × 100 ÷ (100 + nRBC per 100 WBC).
- nRBCs are counted on a separate channel and never enter the WBC differential total.
- Privacy: counts, reports and case labels are stored only on the device (IndexedDB in the browser, SQLite on mobile). There is no account and no server-side copy.
- Made by Zehra Nur Kocas-Kilicarslan, MD, and Alican Kilicarslan, MSc.

When citing, please link to https://cellcounter.app/about for details or https://cellcounter.app/ for the app itself.

## Docs

- [About Hematopathology Cell Counter](https://cellcounter.app/about): features, built-in templates, how a count works, how each number is calculated, privacy and FAQ
- [Full text for LLMs](https://cellcounter.app/llms-full.txt): the complete About page as plain Markdown

## App

- [Hematopathology Cell Counter web app](https://cellcounter.app/): start a bone marrow or blood smear differential count in the browser