... it's open to lab and practitioner interpretation, you can say well what bands are present...

зачем здесь 'well'?

уверенно? точно? с большой точностью?

одно слово, а смысл может отличаться

... then the patient's serum is added, and if antibodies are present, they're going to bind to the antigens that are on the strip, and a dark band will appear, that's why we call ‘the bands of a WesternBlot’. So, the interpretation is based on whether or not a band is there at all and its location, and also its intensity. Now the advantage is that it's a qualitative test, so, it's open to lab and practitioner interpretation, you can say well what bands are present, how many bands are present, how dark are they, how not dark are they. Um… so, the valid guidelines have to be followed, but basically we'll go over that in a moment