Although ketones are omnipresent in the blood (< 1 mg/dL), levels increase during periods of fasting and prolonged exercise.The nitroprusside test only detects acetoacetate in blood and urine; however, it does not assess beta-hydroxybutyrate, the most accurate indicator of ketone body levels.
The Chase Sapphire Reserveâ  is a hybrid between a rewards card and a premium credit card. For a hefty annual fee of $450, cardholders get access to some of the best rewards rates of any credit card, the highest credit card welcome bonus, and a slew of ancinilary travel benefits. The Chase Sapphire Reserveâ  gives a 4.5% rewards rate on travel and dining out, and 1.5% on everything else.
Your best option might not be an airline credit card at all. The best airline credit cards help you earn free flights, seat upgrades, and more. If you travel consistently on the same airline, the right airline card can be one of the most important cards in your wallet. Those of you traveling on a variety of airlines will want to consider another card, like the two below.