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Nelson Labs Adds New Quantitative Hemoglobin Assay to Improve Cleaning Validations

By Mike Neilson, Section Leader, Healthcare Reprocessing, BS, RM(NRCM) CQPA(ASQ)

How cleanable is your reusable device? Nelson Labs has been helping clients determine this for years through simulated use validations. Devices are contaminated with a test soil, cleaned following prescribed instructions from the device manufacturer, then tested for specific residuals to evaluate the effectiveness of the cleaning procedure.

The FDA requires at least two quantitative markers be evaluated to determine cleaning effectiveness.  There are many possible cleaning markers to choose from including protein, hemoglobin, total organic carbon, carbohydrates, bacterial endotoxin and bacterial reduction.  Of all the markers, hemoglobin is often the most clinically relevant, as it is specific in determining the amount of blood that is remaining on a device after cleaning.

Though Nelson Labs led the industry in the ability to test hemoglobin, the assay was “semi-quantitative” yielding a range of concentrations rather than a specific value.  A new assay has been developed that incorporates a binding reaction between any hemoglobin present and a copper compound.  When an “activator” is introduced, the reaction can be detected on a UV/VIS Spectrophotometer and quantified by comparison to a known standard curve.

The new assay provides increased accuracy while maintaining the sensitivity of the old assay.  It provides fully quantitative results to satisfy the FDA.  And to top it all off, it provides a way to evaluate blood residuals which is very clinically relevant for any blood-contacting reusable device.

Nelson Labs highly recommends incorporating this newly validated quantitative marker into any relevant reusable device cleaning validation.