I haven't seen their device and I won't want to see it, I want to first understand the concept better independently. I am not an expert in biology but I have feeling how such device could be done.
Noname covers sensitivity and new concept "amplification" raising a new puzzle: is amplification done by analog methods (op-apms), digital methods, dilution or/and some other methods?
Summarising the Noname to sensitivity, amplification and background
(I added bolding)
"Theranos is working on modular micofluidic devices/cartridges"
"regardless of how good your device is, at some point you start amplifying junk. The better the primers and other reagents the less junk you amplify, but at the end of the day you want more sample to be more sensitive."
"they aren't/can't multiply the analyte of interest. In these tests, they rely more on dilution or small volumes to perform detection. This is where their ability to reliably dilute and correct for the dilution comes into play. -- if you had perfect detection you might be ok, but you generally want to analyze more blood so that statistics work in your favor and your performance goes up. Most of the other chemistries, proteins, and as mentioned earlier, electrolytes will probably be ok for dilution and detection and in fact this is why there are plenty of small devices already out there that use a drop of blood and perform the same tests."
"They don't publicize that they may need to draw a venous sample (needle in your arm) for some tests and depending on what tests you order, you may need a separate finger prick for each test."
where by (2) more sensitivity can actually be a good thing; by (3) same tests already done by other devices in small size: what is so special with Theranos device? and by (4) one drop of blood not enough for all tests.
"What are limiations of multiplying so little blood?"
- Decision Analysis (DA) and Compositional Blood Analysis (CBA): I see such a device as a Decision Analysis (DA) device where you need to do compositional blood analysis (CBA). You get a lot of vague information on which you do sensitivity analysis. Conventional full blood tests can be seen as devices where the sensitivity is very very low to other factors. It is not surprising that development has lasted about 10 years, sensitivity analysis is very low research project. For example, Chevron's DA model started 1990 and continuing, implementation takes time. For example, scale hydration level to some level in all samples. When you have low-quality information, you need to use ad hoc models (often based on high-quality samples) such as supposed correlations between things to improve prediction accuracy.
1.1. What are Decision factors?
1.1.1. Rheology of blood? Dry or liquid phase samples?
1.1.2. Correlation of red/white shells: I don't use the word "approximation" because the number of red shells correlated with the number of white shells
1.1.3. Density (~1.05 kg/l)
1.1.4. Colour of blood
1.1.5. Hydration level
1.1.6. other factors?
"How can Theranos blood test's be specific and accurate compared to conventional full blood test?"
I think this question mis-framed. It is better to ask "How much extra value does such a device can offer?"
Smaller size and less blood mean convenience. It may be useful with athletes, new markets. More convenient to patients/users even though suffering from some abnormalities due to its intrinsic limitations related to its small-volume measurement method.
What components do you need to multiply?
I think this is an important insight: is it possible to multiply blood somehow ensuring its quality for testing? This would make blood tests less painful for patients. Perhaps this is related to stem-cell research? Perhaps not, the Noname covers this in terms of dilution more closely.