Chemistry of Life

Sunday, January 24, 2016

QC - THE MULTIRULE INTERPRETATION

QC - THE MULTIRULE INTERPRETATION

There are three types of errors in a Clinical Laboratory. They are

1. Crude Error [all the pre-analytical errors]

2. Random Errors [ all the sample and technical errors]

3. Systematic Errors [ its mainly from the Machine side]

How to rule out the errors?

Crude Error—it can be reduced by putting the computerization.[like the data entry and all]

Random Error—Can be checked by two Westgard rules 13s and R4s

Systematic Errors---can be checked by the following rules. 22s, 41s , 10x

The Rules:

• 13s

• 12s

• 22s

• R4s

• 41s

• 10x

13s refers to a control rule that is commonly used with a Levey-Jennings chart when the control limits are set as the mean plus 3s and the mean minus 3s. A run is rejected when a single control measurement exceeds the mean plus 3s or the mean minus 3s control limit.

12s refers to the control rule that is commonly used with a Levey-Jennings chart when the control limits are set as the mean plus/minus 2s. In the original Westgard multirule QC procedure, this rule is used as a warning rule to trigger careful inspection of the control data by the following rejection rules.

22s - reject when 2 consecutive control measurements exceed the same mean plus 2s or the same mean minus 2s control limit.

R4s - reject when 1 control measurement in a group exceeds the mean plus 2s and another exceeds the mean minus 2s.

41s - reject when 4 consecutive control measurements exceed the same mean plus 1s or the same mean minus 1s control limit.

10x - reject when 10 consecutive control measurements fall on one side of the mean.

In addition, you will sometimes see some modifications of this last rule to make it fit more easily with Ns of 4:

8x - reject when 8 consecutive control measurements fall on one side of the mean.

12x - reject when 12 consecutive control measurements fall on one side of the mean.

In situations where 3 different control materials are being analyzed, some other control rules fit better and are easier to apply, such as:

2of32s - reject when 2 out of 3 control measurements exceed the same mean plus 2s or mean minus 2s control limit;

31s - reject when 3 consecutive control measurements exceed the same mean plus 1s or mean minus 1s control limit.

6x - reject when 6 consecutive control measurements fall on one side of the mean.

In addition, you will sometimes see some modification of this last rule to include a larger number of control measurements that still fit with an N of 3:

9x - reject when 9 consecutive control measurements fall on one side of the mean.

7T - reject when seven control measurements trend in the same direction, i.e., get progressively higher or progressively lower.

Tuesday, October 5, 2010

IVF Pioneer Robert Edwards of Britain Wins Nobel Prize in Medicine 2010

STOCKHOLM (Oct. 4) -- Robert Edwards of Britain won the 2010 Nobel Prize in medicine on Monday for developing in-vitro fertilization, a controversial breakthrough that ignited sharp criticism from religious leaders but helped millions of infertile couples in the last three decades have children.

Edwards, an 85-year-old professor emeritus at the University of Cambridge, started working on IVF as early as the 1950s. He developed the technique - in which egg cells are removed from a woman, fertilized outside her body and then implanted into the womb - together with British gynecologist surgeon Patrick Steptoe, who died in 1988.

On July 25, 1978, Louise Brown in Britain became the first baby born through the groundbreaking procedure, marking a revolution in fertility treatment.

"(Edwards') achievements have made it possible to treat infertility, a medical condition afflicting a large proportion of humanity, including more than 10 percent of all couples worldwide," the medicine prize committee in Stockholm said in its citation.

"Approximately 4 million individuals have been born thanks to IVF," the citation said. "Today, Robert Edwards' vision is a reality and brings joy to infertile people all over the world."

Steptoe and Edwards developed IVF from the early beginning experiments into a practical course of medicine and founded the first IVF clinic at Bourn Hall in Cambridge in 1980.

Today, the probability that an infertile couple will take home a baby after a cycle of IVF is 1 in 5, about the same odds that healthy couples have of conceiving naturally.

Prize committee secretary Goran Hansson said Edwards was not in good health Monday when the committee tried to reach him. Bourn Hall said Edwards was too ill to give interviews.

"I spoke to his wife and she was delighted and she was sure he would be delighted too," Hansson told reporters in Stockholm after announcing the 10 million kronor ($1.5 million) award.

"Louise's birth signified so much," Edwards said at Brown's 25th birthday celebration in 2003. "We had to fight a lot of opposition but we had concepts that we thought would work and they worked."

Brown, now 32, reportedly is a postal worker in the English coastal city of Bristol. In 2007 she gave birth to her first child - a boy named Cameron. She said the child was conceived naturally.

"Its fantastic news, me and mum are so glad that one of the pioneers of IVF has been given the recognition he deserves. We hold Bob in great affection and are delighted to send our personal congratulations," Brown said in a statement released by Bourn Hall.

The work by Edwards and Steptoe stirred a "lively ethical debate," the Nobel citation said, with the Vatican, other religious leaders and some scientists demanding the project be stopped. When the British Medical Research Council declined funding for Steptoe and Edwards, a private donation allowed them to continue their research.

The Vatican is opposed to IVF because it involves separating conception from the "conjugal act" - sexual intercourse between a husband and wife - and often results in the destruction of human embryos that are taken from a woman but not used.

There was no immediate comment from the Vatican's top bioethics officials Monday to word of the Nobel.

In a statement, Bourn Hall said one of Edwards' proudest moments was discovering that 1,000 IVF babies had been born at the clinic since Brown, and relaying that information to a seriously ill Steptoe shortly before his death in 1988.

"I'll never forget the look of joy in his eyes," Edwards said.

William Ledger, head of reproductive and developmental medicine at Sheffield University, called the award "an appropriate recognition" for Edwards.

"The only sadness is that Patrick Steptoe has not lived to see this day because it was always a joint team effort between the two of them," Ledger said.

Steptoe was not honored with a prize because Nobel rules were amended in 1974 to prohibit posthumous prizes.

Other experts criticized Britain for not honoring Edwards earlier with a knighthood.

"It's a shame Britain hasn't recognized him in a more explicit fashion," said Francoise Shenfield, infertility expert with the European Society of Human Reproduction and lecturer in medical ethics at University College London.

In an interview with The Times of London in 2003, Edwards said he was "not terribly bothered" about not getting a knighthood.

"I'm a very left-wing socialist and I won't shed a tear. But if you can organize a Nobel, please go ahead," he joked.

Aleksander Giwercman, head of reproduction research at the University of Lund in Sweden, said Edwards' achievements also provided tools for other areas of research, including cancer and stem cells.

"Many of the illnesses that develop when we are adults have their origin early on in life, during conception," Giwercman said.

The controversy over in-vitro technology has not dimmed despite its popularity. In the last few years, the increasing use of IVF has also raised discussions about what age it's appropriate to become a mother. In 2006, a 67-year-old Spanish woman became a mother after she used IVF technology to conceive twins, only to die herself two years later.

The medicine award was the first of the 2010 Nobel Prizes to be announced. It will be followed by physics on Tuesday, chemistry on Wednesday, literature on Thursday, the Nobel Peace Prize on Friday and economics on Monday Oct. 11.