Counting Chambers

Graticules have numerous counting chamber types in our range:

• Sedgewick Rafter chambers for water analysis, culture inspection and for other applications where particles per unit volume in fluid must be determined.
• Howard Cell, typically used for the measurement of mold spores in fruits and vegetables.
• Sperm Counting chambers, Makler and Shukratara, as the name suggests, used for sperm counts and mobility.
• Haemocytometers, numerous types and designs used for blood analysis and numerous other applications in the medical and scientific fields.

Sedgewick Rafter chambers

Strictly speaking these should be called Sedgwick (without an ‘e’) Rafter but over the years the spelling has been mis-used.

Sedgewick–Rafter counting chambers are specialised microscope slides designed for quantitative analysis of microorganisms and particles in liquid samples, particularly in water analysis and biological studies. They feature an engraved grid that defines an exact sample volume of 1 mL (50 × 20 × 1 mm), subdivided into 1,000 equal squares, each representing 1 microlitre (µL). This structure allows accurate estimation of organism concentration.

Originally developed by William Sedgwick and George Rafter for assessing drinking water quality, these chambers are widely used to count algae, bacteria, zooplankton, and other particulate matter in transparent fluids. The sample is carefully introduced into the chamber and allowed to settle before microscopic examination. Organisms are counted within selected grid areas, and the results are extrapolated to determine the total concentration. Proper filling techniques and the use of a cover slip help prevent air bubbles and ensure accurate measurements. Sedgwick–Rafter chambers are manufactured from durable optical glass for repeated laboratory use or from plastic for cost-effective or educational applications.

Key Features and Uses

• Purpose: Quantitative counting of particles, algae, bacteria, and zooplankton in water samples; culture inspection; and general environmental analysis.
• Volume: Precisely holds 1 mL (1,000 µL) of sample when used with a cover slip.
• Grid: A 1 mm grid subdivides the chamber into 1,000 squares, each corresponding to 1 µL.
• Material: Available in high-quality optical glass for long-term use or economical plastic for single-use or teaching environments.

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Click here for our YouTube video showing how to use the chambers

Howard Cell

The S60 Howard Cell, used in conjunction with the K20 cover glass, is widely employed worldwide for mould counting in food quality control, particularly in tomato products and other fruit-based preparations. This method is based on the technique originally developed by B. J. Howard in 1911.

Note: The complete system consists of both the Howard Cell and the appropriate cover glass. The cell is supplied without a cover glass, which must be ordered separately. When the K20 cover glass is correctly positioned, it creates a precisely defined liquid layer with a thickness of 0.1 mm over the central island.

Click here for Howard Cell details and ordering on our website

Click here for full Howard Cell product information

Sperm Counting chambers

A sperm counting chamber is a specialized microscope slide designed for semen analysis, featuring a precision-etched grid and a defined chamber depth. Used with a microscope these chambers enable accurate measurement of sperm concentration and assessment of motility under standardised conditions that allow free sperm movement, supporting reliable fertility evaluation.

Key Features and Types

Makler Chamber: A widely used, reusable chamber with a depth of only 10 µm. Its shallow depth confines sperm to a single focal plane, allowing rapid counting and clear motility assessment from undiluted samples while maintaining natural movement.

Shukratara Chamber: Identical to the Makler Chamber in terms of use and specification, but slightly cheaper.

Click here for Comparison Report, Makler v Shukratara

Haemocytometers

Haemocytometers are precision glass slides engraved with grids that are used to manually count cells, microorganisms, or particles suspended in a liquid sample. They function by creating a precisely defined volume of fluid between the chamber surface and a cover slip. By counting the number of cells within specific grid areas, users can accurately calculate sample concentration, typically expressed as cells per millilitre (cells/mL).

Several chamber designs exist, with the Neubauer haemacytometer being the most widely used. These chambers feature grid patterns divided into multiple zones tailored for counting different cell types, such as red and white blood cells. Standardized counting rules—particularly for cells touching boundary lines—ensure accuracy and reproducibility.

How Counting Chambers Work

• Sample Introduction: A diluted cell suspension is pipetted into the chamber, filling the space between the engraved grid and a specialized cover slip by capillary action.
• Defined Volume: The chamber’s precisely manufactured depth (e.g., 0.1 mm for a Neubauer chamber) creates a known volume of liquid over each grid area (e.g., 0.1 µL per large square).
• Microscopic Counting: Using a microscope, cells are counted within designated grid squares.
• Calculation: The cell count is combined with the known chamber volume and any dilution factor to determine the concentration of cells in the original sample.

Key Components and Features

• H-Shaped Moat: Forms the counting area and helps distribute the sample evenly.
• Etched Grid: A precisely engraved pattern, typically consisting of 3 × 3 large squares, each subdivided into smaller squares for detailed counting.
• Chamber Depth: A critical parameter that defines the sample volume above the grid (commonly 0.1 mm).
• Triple Boundary Lines: Central guide lines on grid borders help define counting rules (e.g., include cells touching the bottom and left lines, exclude those touching the top and right).

Common Types of Counting Chambers

• Improved Neubauer: The most commonly used design, featuring nine large 1 mm × 1 mm squares with specialized regions for counting erythrocytes (RBCs) and leukocytes (WBCs).
• Fuchs–Rosenthal: Offers a larger counting area and is often used for dilute samples such as cerebrospinal fluid (CSF).
• Bürker: Features a different grid layout and is suitable for counting cells in less dilute samples, including blood.
• See our web site for the full range.

Applications

• Blood cell counts (red blood cells, white blood cells, and platelets)
• Sperm concentration and mobility analysis
• Yeast and bacterial cell counting
• Cell concentration and viability assessment in cell culture

The complete range of Counting Chambers are shown by clicking this link