Doesn't matter if it's wet food or dry food, the recommended max carb percent is <10%.
You can get a rough idea of the carb % in a dry food by adding up the guaranteed analysis percentages. It's not perfect, but gives you an idea of the carb content. Yes, Hillary is correct that you really want the "as fed" values from the manufacturer but for a quick idea of the carb content, you can add up the guaranteed analysis percentages and subtract from 100.
For example, the Addiction Venison Grain Free is 30% protein, 15% fat, 11% ash (wow that's really high!), 3.5% fiber, 10% moisture for a total of 69.5. subtract from 100 and that gives you 30.5% carb content. Not low carb at all. This is what we would consider very high carb content.
Go Grain Free Chicken Turkey and Duck is 48% protein, 18% fat, 9% ash (wow that's really high too!), 1.5% fiber, 10% moisture for a total of 86.5. subtract from 100 and that gives you 13.5% carb content. This is what we would consider medium carb content. Better than the Addiction Venison Grain Free by far.
Evo Turkey and Chicken Cat and Kitten dry food is 50% protein, 22% fat, ash content not listed, 2.5% fiber, 10% moisture for a total of 84.5. subtract from 100 and that gives you 15.5% carb content. This is what we would consider medium carb content.
You didn't say which of the Epigen foods you are feeding, but the Epigen Starch Free may be the one. That is 60% protein, 15% fat, ash content not listed, 4% fiber, 10% moisture for a total of 89. Subtract from 100 and that gives you 11% carb content. This is what we would consider medium carb content, just barely above the <10% carb limit we like to see. Don't see how Epigen can claim this food is starch free, since it contains potato protein.