
When a Lot of 571 badges is manufactured, a representative number of badges are tested for background levels of formaldehyde and other significant interferences. For formaldehyde background, the average and standard deviation of the background levels must pass established criteria before the lot is approved for customer use. The average value of the formaldehyde background is listed below. Laboratories that use and resell our badges to their customers can use the values below to blank correct their results or just verify their lab is getting the same level of background.

All media that collects formaldehyde has some background formaldehyde. Since Assay Technology manufactures our media inside of glove boxes filled with Nitrogen gas, the background levels are very low and consistent.
571 Badge Formaldehyde Background Level |
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Lot | Expiration Date | Initial Background Level, ug | 6 Month Shelf Life Background Level, ug |
2C23 | 02/29/24 | 0.029 | 0.035 |
3H23 | 03/31/24 | 0.029 | 0.027 |
4C23 | 04/30/24 | 0.036 | 0.033 |
6L23 | 06/30/24 | 0.032 | 0.030 |
9A23 | 09/31/24 | 0.052 | 0.064 |
10L23 | 10/31/24 | 0.049 | 0.065 |
1B24 | 01/31/25 | 0.040 | 0.054 |
3A24 | 03/31/25 | 0.040 | 0.030 |
4B24 | 04/30/25 | 0.043 | 0.093 |
6B24 | 06/30/25 | 0.038 | 0.084 |
7C24 | 07/31/25 | 0.016 | |
9I24 | 09/30/25 | 0.00033 | |
10C24 | 10/31/25 | 0 | |
11G24 | 11/30/25 | 0.026 | |
12B24 | 12/31/25 | 0.066 |
Note 1: | The lot number format is Month/Letter/Year. So Lot 1C11 was produced in January 2011. |
Note 2: | For each lot, Assay Technology tests a set of aldehyde monitors to assure the level of formaldehyde is within acceptance limits. A background level of 0.0046 ppm is 0.6% of the PEL. The background of formaldehyde for a specific lot is subtracted from all samples tested at AT Labs. |