Often, the literature reports diagnostic test characteristics as sensitivity and specificity rather than likelihood ratios. You could compute them by constructing a two by two table as we did above.
 

	SLE	No SLE
Positive ANA	2822	6798
Negative ANA	58	90322
	2880	97120	100000

Going back to the original definition of likelihood ratio, we can compute the probability of a positive ANA test in patients with SLE: (2822 / 2880) or 0.98. We can also compute the probability of a positive ANA test in patients without SLE: (6798 / 97120) or 0.07. The likelihood ratio for a positive ANA is then 0.98 / 0.07 or 14. Using an analagous approach, you should be able to compute the likelihood ratio for a negative ANA (0.02). In more general terms:

LR⁺ = Sensitivity / (1 - Specificity)

LR^- = (1 - Sensitivity) / (Specificity)