Reformulation of Healthcare Diagnostic Kits


A healthcare products manufacturer desired to create their own line of diagnostic kits based on a competitor’s product that was currently on the market. The manufacturer asked Avomeen Analytical Services to reverse engineer one of these kits in order to determine their chemical makeup and reformulate the product for use in their line of cleaning verification tests. While the intended application of this new product varied slightly, they wanted the re-engineered kit to maintain the same detection limits as the original. The detection kit analyzed was used by medical facilities to detect trace levels of a specific protein analyte(s) left on surfaces after cleaning, and had a detection limit of 1µg.


The company provided Avomeen’s chemists several of the detection kits: which each included an indicator solution and a pre-moistened swab. These items were deformulated using various analytical instrumentation and methodology to determine the exact composition of the solution. The company also provided positive testing strips in order to confirm the reformulated product’s efficacy.

It was determined that the swab solution’s composition was water, to verify this a dry swab was moistened with water and used for the testing of an analyte in the sample detection kit. The result was the same as that of using the provided pre-moistened swab.

To determine the composition of the indicator solution, multiple analytical methods were employed. The pH of the indicator solution was measured and found to be acidic. The samples were then analyzed by Gas Chromatography – Mass Spectrometry (GC-MS) in order to identify the volatile components of the indicator solution. The sample was injected as received and was identified as a specific acidic compound. The acidic compound identified was the only volatile component of the indicator solution; this compound was then quantified via titration.

To determine the non-volatiles content of the indicator solution, 5 test kits were dried at 110 °C for 24 hrs. Based on the measured volatiles content and acid content, the water content was calculated. The dried residue from the indicator solution was then examined by Fourier Transform – Infrared Spectroscopy (FT-IR) and identified an acidic compound to be present. Due to the estimated small amount of indicator determined to be present in the solution, identification could not be made through this method due to sample size.

To identify this acidic compound and the elemental signature of any other the non-volatile compounds present in the indicator, the prepared sample was analyzed using Energy Dispersive X-Ray Analysis (EDXA). This test identified sulfur and bromine as present in the indicator solution. This information pointed to the potential of a brominated dye as the indicator.

In order to identify the dye component of the indicator solution, the UV/Visible absorption spectra of the solution was taken both as received and as reacted to hemoglobin. The maxima were measured for the as received solution and for the used solution. The chemist found two dyes that could be possible matches. Further testing through application of the potential dyes was used to identify the best match to the sample product.

At this stage the color of the reformulated sample was yellow, which did not match the orange hue of the sample kit’s solution. In order to match color preference, an additional dye was added to the solution to add the orange color without impacting the reaction or sensitivity to the detection of the analyte(s). The dye was chosen based on the active pH range of this dye when used as an indicator. The active range was similar to that of the previously identified primary dye in the product.

The final reformulation of the indicator was formulated based off of the quantitative results for the acidic compound and experimentation with dye concentrations in order to color match the new formulation to the original product.

The reformulated sample was then tested using dried control samples. The limit of detection was tested using the solid Positive Control strip provided by the client. Both the sample detection kit and the reformulation detected the analyte standard and showed similar detection limit at 1 µg of standard. This product reformulation provided our client with their own formulation enabling them to manufacture cleaning verification test kits for medical products that was equivalent in efficacy to the competing product. The client was pleased with the end result and now holds all rights to the formulation to be produced by their manufacturer and sold to medical professionals nationwide.