                              In the
    United States Court of Appeals
                For the Seventh Circuit
                           ____________

No. 06-2820
MICKEY ERVIN,
                                              Plaintiff-Appellant,
                                  v.

JOHNSON & JOHNSON, INCORPORATED
and CENTOCOR, INCORPORATED,
                                Defendants-Appellees.
                   ____________
             Appeal from the United States District Court
      for the Southern District of Indiana, Terre Haute Division.
              No. 04 C 205—John Daniel Tinder, Judge.
                           ____________
       ARGUED JANUARY 3, 2007—DECIDED JULY 9, 2007
                     ____________


    Before, BAUER, KANNE, and EVANS Circuit Judges.1
  BAUER, Circuit Judge. Mickey Ervin brought a products
liability action against Johnson & Johnson, Inc. and
Centocor, Inc., claiming that his prescription medication
Remicade caused a blood clot that required the partial
amputation of his leg. Defendants moved in limine to
exclude testimony from plaintiff ’s expert and filed a mo-
tion for summary judgment. The district court granted
both motions. Ervin now appeals these rulings. We affirm.


1
  Judge Rovner was a member of the original panel. She recused
herself after oral argument and has not participated in the
decision of the appeal. Judge Bauer took her place.
2                                                No. 06-2820

                      I. Background
  Ervin suffers from Crohn’s disease, autoimmune
hypothyroidism, and diabetes. His doctors tried various
medications to manage his diseases, without success. In
January 2001, Dr. Lee McKinley, Ervin’s internist and
critical care specialist, suggested treating Ervin with
Remicade. Remicade is a prescription drug approved by
the FDA for treatment of Crohn’s disease and is manu-
factured by Centor, a wholly-owned subsidiary of Johnson
& Johnson. Ervin’s gastroenterologist discussed with Ervin
the option of treating him with Remicade. Ervin agreed
to the treatment and underwent his first infusion of
Remicade on March 21, 2001 and his second infusion on
April 25, 2001.
  On April 30, 2001, Ervin complained to Dr. McKinley of
pain in his hands and legs. The next day, Ervin was
hospitalized and diagnosed with arterial thrombosis, which
are blood clots located in the artery of his left leg. Dr.
Laurie Morrison, a vascular surgeon, performed three
thrombectomies, attempting to remove the clots from the
arteries of his left lower leg. These efforts failed, and Ervin
underwent a below-the-knee amputation.
  Lab reports taken from his hospitalization in May 2001
indicated that Ervin had a low Protein S activity level of
61%. Protein S is a naturally-occurring anticoagulant,
which is a substance that prevents clotting. Low Protein S
indicates a higher tendency to clot. Ervin also had an
elevated platelet count of 674,000, which also increases
the risk of blood clots.
  On the issue of causation, Ervin relied on a single
expert: Dr. Lee McKinley. At his deposition, Dr. McKinley
opined that “to a reasonable degree of medical certain-
ty . . . the use of the Remicade was the major contributing
factor to Ervin’s thrombotic arterial occlusion and sub-
sequent below knee amputation.” In reaching this conclu-
No. 06-2820                                               3

sion, Dr. McKinley relied on the process of differential
diagnosis. Differential diagnosis generally provides
a framework in which all reasonable hypotheses are “ruled
in” as possible causes of a medical problem and some of
these possible causes are then “ruled out” to the extent
scientific evidence makes it appropriate to do so. The
goal is to identify the last remaining, or most probable,
“ruled in” cause of a medical problem.
   Dr. McKinley “ruled in” Remicade as a possible cause of
Ervin’s arterial thrombosis. In support of this opinion, Dr.
McKinley relied on the temporal proximity between the
drug infusion and the development of the clot and an
Internet Google search that revealed one case report of
an arterial clot following Remicade infusion. He also re-
lied on a handful of “line entries” from FDA printouts.
The line entries contained basic information that omitted
patient histories, descriptions of treatment, and analysis.
Dr. McKinley admitted that the line entries do not ac-
count for preexisting diseases or co-morbidities that
could have causes the patients’ problems. He did not
rely on any study, textbook, medical article, or paper
indicating that Remicade is associated with an increased
risk of thrombosis.
  Dr. McKinley testified that he did not “rule in” Crohn’s
disease as a possible cause because he was not aware of
the association between Crohn’s disease and arterial
thrombosis. He believed that Crohn’s disease predisposes
patients to venous thrombosis but not to arterial thrombo-
sis. When Dr. McKinely was shown evidence demonstrat-
ing the association between Crohn’s disease and arterial
thrombosis, he testified that he wished he had known
about this association earlier and that this evidence
required him to “reinterpret this case in a completely
different way.”
  Dr. McKinley testified that he did not “rule in” Ervin’s
elevated platelet count or his diabetes as a possible cause
4                                               No. 06-2820

of his thrombosis, even though both of these conditions
are associated with an increased risk of clotting. Dr.
McKinley even acknowledged that Ervin’s prior episodes
of diabetic ketoacidosis are associated with an increased
risk of clotting.
   While acknowledging that a Protein S deficiency can
cause arterial clotting, Dr. McKinley testified that he ruled
it out as a possible cause of the thrombosis because Ervin’s
Protein S profile was “normal.” When he was shown
May 2001 lab reports that indicated that Ervin’s Protein
S profile was abnormally low, he asserted that it was not
“clinically significant.” When he was shown an August
2002 report indicating that Ervin’s Protein S level was
abnormally low in a “clinically relevant” way, he changed
his opinion and testified that he could not “rule out” the
underlying Protein S deficiency as a possible cause of
Ervin’s thrombosis.
   Dr. McKinley’s initial opinion on causation changed
during his deposition. He admitted that he “didn’t know
if [Remicade] caused [the thrombosis] . . . I didn’t know.
I still don’t know.” Following his deposition, Dr. McKinley
executed an affidavit stating that he reviewed additional
materials and that they “seem to further support his
opinion” that Remicade was “one of the substantial
factors in contributing to Mr. Ervin’s thrombotic arterial
occlusion and subsequent below the knee amputation.”
  The district court found the expert’s opinion unreliable
and dismissed the case. Ervin filed this timely appeal.


                     II. Discussion
 We first review the district court’s implementation of the
Daubert v. Merrell Dow Pharms., Inc., 509 U.S. 579, 113 S.
Ct. 2786, 125 L. Ed. 2d 469 (1993), framework de novo.
United States v. Hall, 165 F.3d 1095, 1101 (7th Cir. 1999).
No. 06-2820                                               5

The first step is satisfied here because, in accordance with
the Daubert framework, the district court identified the
relevant analysis and focused its inquiry on whether Dr.
McKinley’s testimony was reliable. Durkin v. Equifax
Check Servs., 406 F.3d 410, 420 (7th Cir. 2005) (citing
Ammons v. Aramark Unif. Servs., 368 F.3d 809, 816 (7th
Cir. 2004)).
  Having determined that the district court properly
applied Daubert, we next review the district court’s
decision to bar an expert for an abuse of discretion. United
States v. Young, 316 F.3d 649, 656 (7th Cir. 2002). District
court judges “enjoy wide latitude and discretion when
determining whether to admit expert testimony.” Wintz
by & Through Wintz v. Northrop Corp., 110 F.3d 508, 512
(7th Cir. 1997).
  The admissibility of expert testimony is governed by
Federal Rule of Evidence 702 and Daubert. Under this
framework, courts determine whether the expert testi-
mony is both relevant and reliable. It is a three-step
analysis: the witness must be qualified “as an expert by
knowledge, skill, experience, training, or education,” Fed.
R. Evid. 702; the expert’s reasoning or methodology
underlying the testimony must be scientifically reliable,
Daubert, 509 U.S. at 592-93; and the testimony must
assist the trier of fact to understand the evidence or to
determine a fact in issue. Fed. R. Evid. 702. In determin-
ing reliability, Daubert also sets forth the following non-
exhaustive list of guideposts: (1) whether the scientific
theory can be or has been tested; (2) whether the theory
has been subjected to peer review and publication; (3)
whether the theory has been generally accepted in the
scientific community. Daubert, 509 U.S. at 593-94. The
district court found that Dr. McKinley was qualified to
provide an expert opinion but his methodology was unreli-
able. Specifically, the district court found that Dr. McKin-
ley’s differential diagnosis was tainted by “critical flaws”
6                                              No. 06-2820

leaving “his opinions unreliable under the standards
set forth in Rule 702 and Daubert.” We agree.
  A differential diagnosis satisfies a Daubert analysis if
the expert uses reliable methods. Under Daubert, expert
opinions employing differential diagnosis must be based
on scientifically valid decisions as to which potential
causes should be “ruled in” and “ruled out.” Ruggiero v.
Warner-Lambert Co., 424 F.3d 249, 254 (2d Cir. 2005).
Determining the reliability of an expert’s differential
diagnosis is a case-by-case determination.
  We agree with the district court that Dr. McKinley had
no reliable basis for his expert opinion. He could not
point to any epidemiological data supporting his opinion,
and he was not able to articulate any scientifically physio-
logical explanation as to how Remicade would cause
arterial thrombosis. The mere existence of a temporal
relationship between taking a medication and the onset of
symptoms does not show a sufficient causal relationship.
The district court did not abuse its discretion in finding
that Dr. McKinley’s testimony was unreliable. In the
absence of any other expert evidence supporting Ervin’s
causation theory, the district court properly granted
summary judgment.


                      III. Conclusion
    For the foregoing reasons, we AFFIRM the district court.

A true Copy:
        Teste:

                        ________________________________
                        Clerk of the United States Court of
                          Appeals for the Seventh Circuit

                    USCA-02-C-0072—7-9-07
