Donation · Volunteer banks
Paid · Plasma centers
Violet ring · Platelets accepted
Payment not recorded

What this map found

  1. Two economies, one word. Paid plasma centers collect source plasma for drug manufacturing; volunteer banks collect transfusable components and pay nothing. Worldwide 384 sites do both. In the United States, not one address appears on both layers.
  2. Advertised pay and donor pay are two different numbers. CSL advertises $800 and Octapharma $750. Across 116 donor reports the median is $60 a visit at CSL. Both are true: the large figure is a first-month bonus across about eight donations, with conditions.
  3. Plasma centers are sited in poorer neighborhoods, and it is a company choice. 68% sit in the poorer half of their own county, where chance alone would put 50%. Two centers in three, where chance says one in two. A gap that size across a thousand centers does not happen by accident (p = 10−60). By operator: CSL at the 30th percentile, Octapharma 31st, Grifols 32nd, with the newer chains close behind (KEDPlasma 33rd, Parachute 35th, Freedom 37th). BioLife sits at the 48th, which is essentially neutral.
  4. Volunteer centers track schooling slightly more closely than income, though the two are 80% the same thing. They sit at the 54th income percentile of their county and the 59th for degrees, and they stay above the paid layer on education inside every income band (median gap 7.4 points). Across 46,783 tracts income and degrees correlate at r = 0.80. They are largely the same map, so this is one gradient seen twice rather than two separate findings. It matches who gives: 1.5% of adults without a high-school diploma donated last year against 7.2% of doctorates.
  5. What this means for a person, and what it cannot say. The blocks around a plasma center are poorer and less insured than the rest of their county: roughly one person in ten without insurance, against one in sixteen around a volunteer bank. That describes places. The map shows where centers are. It says nothing about who walks in.
  6. Most of the world's payment status is simply unrecorded. 2,201 of 5,021 sites have no compensation tag in OpenStreetMap. They are drawn as hollow rings and never counted as either layer.

Center siting tested against census tracts within each center's own county, so region and city size drop out. Donor rates computed from the 2016 National Health Interview Survey public-use file (33,028 adults); the weighted rate reproduces NCHS's published 5.7% at 5.6%. Every source is free and keyless, with no paid APIs.