Product Center

The CrystalSpec™ Nephelometer is a battery-powered, portable device designed to measure the turbidity of microbial suspensions equivalent to McFarland standards 0.5 through 4.0. The instrument can be used for any laboratory procedure that requires inoculum density adjustments within this range.

The visual comparison of organism suspensions to turbidity standards is an accepted method of estimating organism densities. The most widely accepted standard is the McFarland standard.¹ A McFarland standard is prepared by adding barium chloride to aqueous sulfuric acid. The density of the resulting barium sulfate precipitate can be used to approximate the colony count of a prepared suspension; e.g., McFarland 1 is the equivalent of approximately 3 x 10⁸ CFU/mL. Other standards have been used for density measurements, including titanium dioxide² and latex particle suspensions.³

The instrumented measurement of turbidity relies on the ability of particles to scatter light while in suspension. The measurement of this scattered light is referred to as nephelometry.⁴ In order to obtain an accurate density measurement, a reliable method of calibration must be used.

in vitro Diagnostic

Read all instructions before use and follow precisely.