Excellent question. It's good to see attention being given to the different types of PRP systems. It can be confusing with so many different PRP systems on the market. It would be great if they all produced consistent, concentrated PRP but unfortunately this is not the case. This is apparent even on the visual appearance of PRP. An interesting demo was done at a major conference in Europe where one researcher donated blood on stage and PRP was prepared using 8 different PRP systems. The PRP samples all looked different, ranging in color from straw-yellow to deep blood-red and concentrations of platelets, red blood cells within also varied by several orders of magnitude. A good starting point would be what is PRP? "Platelet Rich Plasma" is defined exactly as it sounds, plasma which contains a high concentration of platelets; the classic definition (Marx, 2001) is that PRP should contain at least 1 million platelets per microliter (µL). A microliter is a cubic millimeter. In comparison, whole blood usually has a concentration around 200,000 /µL, so this represents 5x increase in concentration, which is usually achieved by separating the blood components in a centrifuge. Although the principle is quite simple, in practice it's a delicate process, and it's easy to spin a bit too long or hard. When this happens, instead of increasing concentration, the platelet concentration actually decreases as platelets get lost in the red cell layer or stuck in the gel of commonly used tubes. Unfortunately this is common in many systems. In 2019, a comprehensive review from the Mayo Clinic School of Medicine looked at 33 different PRP systems available on the market today. Only 10 of the 33 systems met the effective concentration levels described above. And 3 of these systems produced PRP with a concentration of platelets which was actually less than the starting blood sample. The concentration and overall dose of platelets in PRP is very important. After all, it's the platelets which contain the growth factors and cytokines which are responsible for all of the benefits of a PRP treatment. This is why we test every sample of PRP with a hematology analyzer for concentration and purity before use. If there are not enough platelets the sample is not used. Without a hematology analyzer, one can only make an educated guess about the concentration, but in general, only double spin systems are capable of approaching a concentration of 1 million/µL. Also, one has to start with enough blood in the first place, in order to have enough platelets in the initial sample. This is because due to the laws of physics, no system is perfect and at least 10-20% of the platelets are usually lost in any preparation method. Some types of PRP treatments don't seem to be as dependent on high concentration and may even be better suited to lower concentration, such as under eye treatments, microneedling aka "Vampire Facial." But for the P-Shot, O-Shot or hair, higher concentration is recommended and the research does seem to show that better results are achieved. In conclusion, for certain PRP procedures, high concentration is recommended. The best confirmation of concentration would be with on site testing using a hematology analyzer. In order to reliably obtain platelet concentrations over 1 million/µL some type of double-spin preparation system is used, and a minimum starting volume of 50-60mL of blood is required to yield 10mL of high concentration PRP for the P-Shot. Hope this helps.