Source: https://guthlabs.ai/docs/instruments/cell-counting-hemocytometer-calculator/

instrument / verified-clean

# Cell Counting / Hemocytometer Calculator

The current ledger marks this instrument verified clean within the source-bound verification corpus.

Status: **VERIFIED_CLEAN**Lifecycle: **verified-clean**

## Inspectable records

[01**Overview**Purpose and lifecycle](<https://guthlabs.ai/docs/instruments/cell-counting-hemocytometer-calculator/>)[02**Mechanism**Method and assumptions](<https://guthlabs.ai/docs/instruments/cell-counting-hemocytometer-calculator/mechanism/>)[03**Implementation**Binding and validation](<https://guthlabs.ai/docs/instruments/cell-counting-hemocytometer-calculator/implementation/>)[04**Qualification**Evidence and errata](<https://guthlabs.ai/docs/instruments/cell-counting-hemocytometer-calculator/qualification/>)

## Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

**Area**: Biology, Medicine & Pharmacology (educational estimates only — every panel labeled not-medical-advice)

**Tranche**: tranche-5

**Evidence ID**: t5-163

**Ledger rows**: 1

No ledger note is attached.

## Review findings

The concentration formula is conditionally standard, but the specification needs explicit chamber geometry, dilution-factor convention, volume units, total-cell formula, and viability formula before implementation. The educational and not-medical-advice label is appropriate but does not replace these technical assumptions.

### Formula and scope findings

- The cells/mL formula is standard only when the counted square has a volume of 0.1 µL, as in the standard Neubauer hemocytometer; the chamber type and square dimensions are not specified.

- The formula for total cells is omitted. It should be total cells = cells/mL × total volume in mL.

- The formula for viability percentage is omitted despite viability being listed as an output. The standard formula is viability % = live cells ÷ (live cells + dead cells) × 100.

- The meaning of dilution factor is ambiguous: it must be the reciprocal of the sample fraction, so a 1:1 sample-to-diluent mixture has dilution factor 2, not 1.

- The meaning of avg_count is not explicitly defined; it should be the arithmetic mean of valid square counts, typically sum of counts divided by number of squares.

### Unit assumptions

- The factor 10^4 assumes a standard hemocytometer counting square of 1 mm × 1 mm × 0.1 mm, with concentration reported in cells/mL.

- Dilution factor is dimensionless and represents the reciprocal of the fraction of original sample in the counted suspension.

- Total volume must be supplied in mL before calculating total cells; volumes in µL require conversion using 1000 µL = 1 mL.

- Cell counts are nonnegative counts, and number of counted squares is a positive integer.

## Boundary hardening

**BREAK_CLAIMED** · SELF_FLAGGED

The instrument has an undefined-result failure when number_of_squares is zero and a potentially 100-fold numerical discrepancy when the dilution notation 1:10 is interpreted using the wrong convention.

## Errata and corrections

No applied erratum is attached to this unique-name record.

## Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

````
{
  "inputs": {
    "counts_per_square": [
      84,
      91,
      88,
      87
    ],
    "number_of_squares": 4,
    "dilution_factor": 2,
    "total_volume_mL": 5
  },
  "expected_outputs": {
    "cells_per_mL": 1750000,
    "total_cells": 8750000
  },
  "working": "Average count = (84 + 91 + 88 + 87) ÷ 4 = 350 ÷ 4 = 87.5. Cells/mL = 87.5 × 2 × 10,000 = 1,750,000 cells/mL. Total cells = 1,750,000 × 5 mL = 8,750,000 cells."
}
````

## Related workflows

No source-defined multi-instrument workflow membership is recorded.

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json · VERIFIED_CLEAN`

- `evidence-tranche5/tranche5-results.json`

- `BOUNDARY_HAZARD_CATALOG.json`