Oksana –
Femoral nerve tension testing is a good way to help with your diagnosis of meralgia paresthetica, as you said. I would also palpate the area to see if you could possibly manually compress the lateral femoral cutaneous nerve as well. Is she able to recall any position or activity she is in when she feels the numbness?
Were you able to reproduce or exacerbate the lateral thigh pain/numbness? Did PA pressure to the lumbar segments change the symptoms in her thigh? Also, the glute min could refer pain to the lateral thigh. I would palpate and apply fair pressure to tender areas of the glute min and hold for maybe 15 secs or so, if tender, and see if that reproduces it.