I recently did blood testing for NK cells in Sydney. I was sent to St George Hospital which has a pathology lab that specialises in this. It was bulk billed.

The blood testing takes place on a Tuesday or Thursday of each week and as other people have said should be done after cycle day 21 up to the start of your period as this is when NK cells rise. I think the date of testing is more crucial for biopsy rather than the blood test.

The results came through in a matter of days. I am a patient of IVF Australia and although not seeing Dr Sacks myself my case was run via him as the NK protocol is his.

Depending on the results of your blood test you may need to have the biopsy - it was explained to me a biopsy is only necessary if blood tests are borderline. As my levels were high (21%) there was no need for further testing.

I was treated with prednisolone (a steroid) from retrieval and clexane and asprin from transfer. Unfortunately this cycle didn't work so I am currently seeking info on adding intralipids into the next round. It seems in America intralipid transfusions have now replaced iVIG as the treatment of choice.

To add further confusion it seems Doctors around the world are split on NK cells with many not believing they are a factor in implantation problems.

Good luck! And please pass on any info my way too.