Hello from JustAnswer. This is Dr. Love and I will be glad to assist you today.
The short answer is that your husband is partly correct, but you will be fine once the GC/MS test is done.
When doing drug testing, the first step is a screening test, which is an immunoassay test. The advantage of the immunoassay test is that it is faster and cheaper. The disadvantage of an immunoassay test is that there is a fair amout of false results. Therefore, any positive test would need to be confirmed by a more accurate test, such as the GC/MS test.
While many false positive tests are never able to be explained, there are certain drugs that are known to cause false positive. And one of the known drugs is the Sudafed, as is all of the other decongestants. All of the decongestants are chemically similar to adrenaline, but are derivatives that are made to focus on the effect on congestion. Amphetamines are also similar to adrenaline, but are derivatives that were made to focus on the stimulating effects. Since they are chemically similar, the decongestants can cross reactive with the immunoassay for amphetamines or methamphetamines, causing a false positive. However, when the sample is sent for the GC/MS test or other confirmatory test, the lab will be able to say that there is no amphetamines or methamphetamines in the sample, so you will be fine.
Therefore, it is possible that you could have a false positive screening drug test, but if so, the confirmatory test will be able to show that you have no drug in your system, and will identify the initial positive test as a false positive.
If I can provide any additional information, please let me know.