Oh, wow...

Okay, I just spent the better part of an hour working on a comment on this (hey, I just passed a hematology course, sooo... ;), and then, as I finally got around to checking out the website, I catch this line in the video (emphasis mine):

"All that's really needed from an individual is a drop of blood from the finger to create a thin smear on a slide for analysis with standard protocols."

That's a lot different from what the linked article claims (again, emphasis mine):

"A single drop of blood from the patient is required then smeared on the microscopy lens."

Smearing the lens directly seemed an interesting idea, although it poses a few challenges I'll touch on shortly. However, a close listen to the video makes it clear that's not what the project purports to do. The Lifelens "hardware" -- the lens -- is just meant to give a phone camera microscopic capabilities. How well that works isn't too clear, but it's definitely not the same thing.

It would actually be quite difficult to get an acceptable specimen on a tiny lens. The standard laboratory method is to place a drop of blood on a slide, then use another slide to draw it out into a thin film. Here's a quick video that shows a pretty good example:

http://www.youtube.com/watch?v=iA6ce-3sYgk

Note how the tech drags the slide back at an angle over the drop, then pushes it forward almost immediately. It takes good timing and a lot of practice to get it right, and then you have to find just the right part of the specimen for a proper analysis. What you get in a typical thin smear is a range of population densities, from a clumpy mess of cells crowding and overlapping each other, to rarefied lines and clusters of cells spaced widely apart. The nice, evenly spaced fields shown in the article are just a small region of the full sample, usally a couple fields behind the feathered edge. Getting that is a challenge just in the laboratory. On a tiny lens in the field? I'll believe that when I see it, and this is just the second step! (Getting the sample is the first) The specimen still has to be stained.

While RBCs with their hemoglobin do en masse make blood red to reddish-purple, individual red cells don't actually show a lot of color without staining. Nor do white cells; they just look a bit larger and grainier than reds. To better examine cell structures, a stained specimen is needed. The standard analytical sample is a Wright stained thin film smear, which requires three different stains be applied and washed in sequence. This stuff doesn't just wash off, either, so don't expect to use the same lens twice. Again, however, that's not what the project actually claims to do. What it does claim, on the other hand, strains credulity in other directions.

Sad to say, but a half-sphere lens on a phone camera does not a microscope make. Without going too deep into details (I hope), proper microscopy requires close attention to the properties of light and lenses. You can't just point a powerful lens at a specimen and expect to get a good image. You also need to ensure sufficient lighting, proper contrast, and control your depth of field!!!

I cannot emphasize that last point enough! Even squashed nearly flat under a cover slip, any specimen you examine is still three dimensional, with details you can only see by shifting the microscopic stage up and down by very small amounts. The depth of field is very narrow. A professional scope's fine adjustment is fine enough to shift focus on a cell from "front" to "back" and anywhere in between. As you might imagine, that requires keeping the stage very, very still. That's why scopes have specimen stages. You won't get that out of a phone camera without clamping it down.

That's what made the article's statement so interesting. If an acceptable specimen could be obtained by smearing the lens directly, the fixed position might allow for proper analysis, but that's not what the project purports to do.

It might be interesting to see where this project goes, but at this point, it's still looking very alpha to me. I'd wait 'til they show this thing in action.

EDIT: Minor spelling error.