Lab Handling Simpson DNA Tests Prepares for the Battle Ahead : Courts: As a leader in commercialized genetic testing, Cellmark Diagnostics’ director knows ‘it’s going to be a dogfight.’ He also says his company is ready to defend its procedures.

Three thousand miles away from the bitter legal skirmishes over O.J. Simpson’s fate, Mark D. Stolorow is quietly digging his own trenches for the upcoming battle.

Stolorow, director of Cellmark Diagnostics, the DNA fingerprint shop testing samples of Simpson’s blood and hair, knows that the case could turn on the work--and reputation--of his company.

And he has seen an army of lawyers try to tear down Cellmark’s credibility hundreds of times before.

“We know when we get to court, it’s going to be a dogfight,” he said in an interview with The Times.

But this particular dogfight--the People of the State of California vs. Orenthal James Simpson--promises to open Cellmark and the “genetic profiling” techniques it uses to closer scrutiny and harsher criticism than the firm has ever faced.

Simpson’s attorneys have assembled a team of seasoned DNA experts. When they come calling, Stolorow said, Cellmark will be ready.

The laboratory, nestled in an office park in this Maryland suburb 30 miles northwest of Washington, certainly is no stranger to the spotlight. After Cellmark analysts matched DNA samples from a Virginia man suspected of being “the Southside Strangler,” he became the first person executed on the basis of DNA test results. When the Pentagon needed help identifying casualties of the Persian Gulf War, it turned to Cellmark.

Prosecutors and defense attorneys have continued to rely on Cellmark even as they argue over its usefulness in the courtroom. The laboratory--the first to commercialize DNA testing using a technique called restriction fragment length polymorphism (RFLP)--handles about 10% of the country’s 4,000 criminal cases involving DNA testing each year. Nationwide, DNA testing cases are split about 50-50 between private and government labs.

Although Cellmark has developed a niche in the criminal forensic science field, its specialty is in high-quality testing for paternity cases, of which it handles about 1,500 each year.

Cellmark scientists have testified in more than 300 cases in 37 states, including California, and several other countries. But its expert testimony and its DNA tests do not come cheap. Each test costs about $550, and a case usually involves at least four tests. Hiring a Cellmark expert to testify in court runs about $1,200 per day.

Stolorow said it is worth the money and offered one reason why: Although the lab’s statistical analyses have been thrown out of court on occasion, Cellmark has never been proven wrong with contradicting evidence from another laboratory.

“Is that trivial?” Stolorow asked. “I don’t think so.”

Proponents point to RFLP’s high rate of certainty--999,999 chances in 1 million, they say--that two matching DNA samples are from the same person.

But the Simpson case comes as the young science of DNA fingerprinting is emerging from a recent flurry of academic and courtroom feuds over the value of what was once a Wunderkind legal tool.

In 1992, a National Academy of Sciences panel urged the nation’s DNA laboratories to calculate more conservative probabilities when explaining to juries what a match means. On the heels of the panel’s report, Cellmark and other testing centers came under fire from professors and attorneys who derided them for practicing an art, not a science.

Respected genetics scholars who once wielded incredible powers of persuasion over juries now face crucifixion on the witness stand.

“Our experts have been cross-examined so intensely that it makes me wonder why they came back,” Stolorow said.

In the Simpson case, Cellmark’s scientists will face off against two opponents they have confronted before: New York attorneys Barry Scheck and Peter Neufeld, both of whom have tried to tarnish the credibility of DNA tests in court before. They have contended that Cellmark and other laboratories are error-prone and that the tests are statistically flawed.

Neufeld accompanied Dr. Henry Lee and Dr. Edward Blake, two defense scientists, to Cellmark recently to reserve 10% of Simpson’s blood samples for possible future testing by another laboratory.

Scheck and Neufeld, who have called for national standards for DNA testing, have said Cellmark’s results “can’t be trusted.”

But Stolorow said the two lawyers have argued both sides of the issue.

“These are guys who have gone to the wall to say, ‘Your honor, you’ve got to allow my client to have DNA testing,’ ” he said. “We’ve gone against these people over and over again.”

Indeed, should the DNA results not link Simpson to the crime scene, another set of defense experts is poised to support the findings.

Cellmark is preparing to defend its credibility against attacks on several fronts.

“They tend to use the standard line, saying DNA testing is not reliable and that there are no national standards enforced,” Stolorow said.

The laboratory is also anticipating questions about its “error rate”--a proportion of tests that yield false readings. Each lab publishes its error rate in accordance with recommendations from the 1992 National Academy of Sciences report. Cellmark’s error rate, as measured by a proficiency test, is under 0.5%.

Cellmark said this error rate indicates high precision, but critics disagree. “An error number of one in 200 is pretty damning evidence to have to fight,” said Dan Krane, an Ohio DNA consultant who has worked on 20 cases, some involving Cellmark.

In a 1987 proficiency test designed by forensic scientists in California, the laboratory made a number of errors. Test administrators sent blood and semen samples to the DNA laboratories and found that Cellmark and some of its competitors mixed up the samples. Stolorow said the test was structured poorly and noted that in 300 samples examined for proficiency tests in the last five years, the lab has made no mistakes.

Since then, the laboratory has changed its procedures. In the past, Cellmark used a small centrifuge to extract genetic material from the samples, put the material in separate test tubes and then combined the material in the tubes. Now it employs a larger centrifuge and requires its scientists to use only one tube to prevent accidental mixing.

Taking further steps to avoid inadvertent mixing, lab technicians also analyze DNA samples from a crime scene separately from those taken directly from the victims and the suspect.

Cellmark has insisted that all movements of DNA samples are witnessed by a second scientist, who watches for misnumbering of tubes or other errors.

Simpson’s defense experts may also grill Cellmark about the statistical methods it uses to develop its conclusions about DNA samples.

To beat back those questions, the laboratory will calculate its results using both its own statistical method and that recommended by the National Academy of Sciences--the closest thing to a national standard.

What remains to be seen is whether it will be enough.

Former FBI laboratory director John W. Hicks said he believes it will.

“Cellmark is very highly regarded,” said Hicks, who will soon be heading to the Alabama Department of Forensic Sciences. “They have been very responsive to the scientific community.”

Others say the laboratory may have to do better.

If the DNA test matches Simpson’s blood with samples from the crime scene, “the defense is going to dig in their heels and say that Cellmark made a mistake,” Krane said. “It’s a respectable organization, but just like the others, they are subject to human error.”