In IPUMS, there are five sets of imputed variables. I am also looking for an income variable for my analysis. Therefore, can I use only one imputed variable such as "“INCIMPPOINT1” instead of 5 sets of imputed variables?
According to the variable description page (click the “show more” links):
The NCHS documentation for the imputed income files directs that analysis of the five versions of each imputed income variable should be done separately, using methods and software that are appropriate for such survey data (for example, SAS-callable SUDAAN or SAS-callable IVEware).
The basic idea behind multiple imputation methods is that you complete the analysis separately for each set of imputed data, and then pool them together using an appropriate pooling method. Most statistical software will have this capability. I would refer you to the links in the variable description page for more info on the imputation in NHIS. You may also want to reach out to the NHIS project directly since they have specific expertise in this: https://www.cdc.gov/nchs/nhis/contact.htm