Differential Cell Counter
Press one key for each cell you see under the microscope. The total and the percentage of every cell type update as you go, and a tune plays when you reach 100 or 200 cells.
Chart: percentage per cell type
Settings: cell types, keys and target
History: saved counts
No saved counts yet. Save and reset puts the current count here.
How to use the differential cell counter
Each cell type has a tile with its own key: by default 1 Neutrophils, 2 Lymphocytes, 3 Monocytes, 4 Eosinophils, 5 Basophils, 6 Bands, 7 Blasts, 8 Other and 9 NRBC. Keep your eyes on the eyepiece and press the key for each cell, or tap the tiles on a phone or tablet. The digits on the number pad work too.
The total at the top counts every type that is part of the differential, with a bar that fills toward the target. At the target (100 cells unless you change it) a tune plays, the bar turns green and, with Stop counting at the target on, further presses are refused so you cannot overshoot. Take back last (or Backspace) removes the most recent cell, and Undo reverses any change, including a reset.
Everything can be renamed in Settings: the cell types, their keys, which types count in the total, and up to 16 types for any other white cell count, a bone marrow count or anything else counted by category. For a plain tally of one thing, use the tally counter, and for several unrelated counts the multi counter.
Percentages, absolute counts and cells outside the total
The percentage of each type is its count divided by the total of the types marked In total, times 100. A type that is not in the total, such as nucleated red cells (NRBC), is shown per 100 counted cells instead, so 4 NRBC seen during a 100 cell white cell differential shows as 4.0 per 100.
If you type a white cell count below the tiles, the table adds the absolute count of each type: the white cell count times the percentage, in whatever unit you typed. When cells outside the total were counted, it also shows the corrected white cell count, which is the white cell count times 100 divided by (100 plus those cells per 100 counted). This is the usual correction for nucleated red cells; follow your own laboratory's procedure for when to apply it.
Save and reset stores the finished count with its sample label in the history (the last 20 counts), Download CSV exports the current count and the history, and Print sheet prints the result table. Print blank sheet gives a paper white blood cell differential sheet with a tally column for counting by hand.
This is a counting aid, not a medical device. It does no diagnosis and has not been validated for clinical use, so check every result the way your laboratory requires.
Keyboard shortcuts
- 1 to 9 (or the keys you set): count one cell of that type
- Shift + a cell key: take back one cell of that type
- Backspace: take back the last cell counted
- U or Ctrl+Z: undo
- F: full screen, M: sound on or off
Holding a key down counts only once, so a key that sticks never adds extra cells.
Questions
Can I change the cell types and keys?
Yes. Open Settings to rename any type, give it a different letter or digit, add types up to 16, remove types, or restore the defaults. The keys are saved in your browser, so the layout is still there next time.
Can I count 200 cells instead of 100?
Yes. Choose 200 under Alert at a total of, or choose Custom and type any total. Choose No target to count without a limit.
Is my data sent anywhere?
No. The counts, sample labels and history stay in your browser on this device and are never sent to a server. A sample label is optional; avoid typing patient names or other identifying details.
Is this cell counter a medical device?
No. It is a free counting aid for practice, teaching and routine tallying. It does not interpret results, and any result used for patient care must be checked under your laboratory's own procedures.
More in Counters
Put this differential cell counter on your website
Free for classrooms, clubs, blogs and shops: paste this code into any page. It works the same inside your site, and counts stay in each visitor's own browser. For a dark version, add ?theme=dark after /differential-cell-counter/ in the code.