Hi Sutrer, welcome to the forum. I'm also on Lantus/Novolog and I find that my Lantus runs out at about the 20 hour mark, so your bg rise in the afternoon could be due to that. Like the others suggested, try moving the timing of your one shot to see if makes a difference. If you still go high towards the end of the 24-hr period, then you could try splitting it. That's what I do now, 50/50, 12 hours apart and I get much more even basal coverage. But if after those changes, you still find that your afternoon readings are high, it could be that you require more insulin at lunchtime. Everybody's insulin needs vary throughout the day. My carb ratios are different for just about every meal and snack, so I'd keep that in mind.
In theory, your total daily insulin intake should be 50:50 basal:bolus, but that will change depending on several factors. I remember an old thread about ratio of basal/bolus insulin and a total daily dose (TDD) calculator, I think you'll find it here in a post from Mick:
http://www.diabetesforums.com/type-o...tus-users.html
