Sorry, no there isn't - and that is why I don't like the term "Self-Blue" for birds based on the Lavender gene. There is NO Blue in Self-Blue - not the way we make it. There WAS Blue used in the beginning of breeding Self-Blue Silkies because of this misconception - so some Self Blues also carry Blue (or splash) - but to me that messes up the genetics and makes it harder to figure out who is carrying what. The gene that makes our Self Blue birds is called Lavender. With one copy you get nothing showing (splits) - with two copies it mutes all colors.
Blue birds cannot create Self-Blue color unless they are carrying the hidden Lavender. Lavender mutes both Black and Red - so all colors will be muted. Blue only mutes Black - red is not changed. That's how you know the difference.
There is a possibility your birds may be carrying hidden Lavender (especially if they are rejects from a Porcelain/Self-Blue Creme breeding pen). If that is the case then the bird will stay the muted gray - never get splashes - and when crossed to a bird not carrying Lavender the gene will go into hiding again and all colors will come back.
If you are seeing red on your black/blue birds then I suspect you have red leakage from under your White birds. Use all of those children to breed only Whites. That red is really really REALLY hard to get rid of - and its a DQ on any solid colored bird. It is fine on the Partridge one - that is the only color that wants that red.
It took so long to type and edit this that Sonoran said the same thing - shorter and better probably. I know the APA/ABA doesn't like the term Lavender - but I don't like the term Self Blue because of the confusion. And there actually are birds out there based on Blue that are Self Blue - the original OEGB Self-Blue were made that way. To learn more (or get more confused) read the Lavender Silkies thread.
