Document ID: ./input/supremecourt_opinions/opinions/11pdf/10-1150.pdf
Page Number: 17

Cite as:  566 U. S. ____ (2012) 

13 

Opinion of the Court 

did the [claim] contain any disclosure relating to chemical
processes at work or the means of setting off an alarm or 
adjusting the alarm limit.”  Diehr, supra, at 192, n. 14; see 
also Flook, 437 U. S., at 586.  And so the other steps in the
process did not limit the claim to a particular application. 
Moreover,  “[t]he  chemical  processes  involved  in  catalytic 
conversion  of  hydrocarbons[,]  . . .  the  practice  of  monitor­
ing the chemical process variables, the use of alarm limits 
to trigger alarms, the notion that alarm limit values must
be  recomputed  and  readjusted,  and  the  use  of  comput- 
ers  for  ‘automatic  monitoring-alarming’ ”  were  all  “well 
known,”  to  the  point  where,  putting  the  formula  to  the
side,  there  was  no  “inventive  concept”  in  the  claimed 
application  of  the  formula.  Id.,  at  594.  “[P]ost-solution
activity”  that  is  purely  “conventional  or  obvious,”  the
Court  wrote,  “can[not]  transform  an  unpatentable  princi­
ple into a patentable process.”  Id., at 589, 590. 

The  claim  before  us  presents  a  case  for  patentability
that  is  weaker  than  the  (patent-eligible)  claim  in  Diehr 
and  no  stronger  than  the  (unpatentable)  claim  in  Flook. 
Beyond  picking  out  the  relevant  audience,  namely  those 
who  administer  doses  of  thiopurine  drugs,  the  claim  sim-
ply tells doctors to: (1) measure (somehow) the current level
of  the  relevant  metabolite,  (2)  use  particular  (unpatenta­
ble) laws of nature (which the claim sets forth) to calculate 
the current toxicity/inefficacy limits, and (3) reconsider the
drug  dosage  in  light  of  the  law.  These  instructions  add 
nothing  specific  to  the  laws  of  nature  other  than  what  is
well-understood, routine, conventional activity, previously
engaged in by those in the field.  And since they are steps
that must be taken in order to apply the laws in question,
the  effect  is  simply  to  tell  doctors  to  apply  the  law  some­
how  when  treating  their  patients.    The  process  in  Diehr 
was not so characterized; that in Flook was characterized 
in roughly this way.