Wednesday, August 06, 2008

Warning over blood-taking method

Organ transplant patients have their blood taken on a regular basis so the medical teams can monitor results and make medication changes or take other action if needed.

I almost fell off the floor when I read the following report.

Recently I received an emergency call on my cell phone saying that my blood tests indicated dangerously high potassium levels and that I had to do something about it immediately. Now, after reading this article, I wonder if my potassium levels were OK all along and did I worry and make diet and drug changes unnecessarily? A physician interviewed on the news today said that patients should refuse to clench and relax their fists if asked to do so. It's an outdated practice.

From BBC News:

People who take blood have been warned not to get the patient to tightly clench their fist during the procedure.

UK researchers who examined 200,000 blood test results found clenching then relaxing the fist could raise potassium levels, potentially confusing results.

Raised potassium levels can indicate kidney or heart problems, the Annals of Clinical Biochemistry study said.

A UK expert said clenching was an outdated practice and staff taking blood should not ask patients to do so.

Hit or Miss

Vanessa Thurlow, a biochemistry expert and co-author of the report, first noticed a problem when GPs were questioning test results for a small number of patients.

When she retested them, their potassium levels were normal - but they had all started to clench their fists before the test.

Vanessa Thurlow, a biochemistry expert and co-author of the report, first noticed a problem when GPs were questioning test results for a small number of patients.

When she retested them, their potassium levels were normal - but they had all started to clench their fists before the test.

It led Ms Thurlow to speak to managers of the phlebotomy - blood-taking - services in her trust, which then instructed staff not to use the clenching method.

Her study looks at 200,000 results from blood tests requested by GPs between 2002 and 2005. The updated training was offered in September 2003.

The percentage of tests showing worryingly high potassium levels fell significantly after the change.

The impact of fist-clenching while giving blood has been known since the 1960s, but she said procedure was being passed on from generation to generation of phlebotomists.

"It seems to be hit or miss whether they get trained to avoid using this procedure," she said.

She said other factors such as exposure to cooler temperatures have been known to cause false raised-potassium levels, but she believes the impact of this hand-gripping is underestimated.

"We think that as a result patients might have to have their medication adjusted. We don't know how widespread a problem this is in other parts of the country."

Blood Flow

Ms Thurlow admitted some patients were very difficult to bleed.

"The pressure on the phlebotomist to obtain some blood somehow, particularly with very nervous patients, can be high.

"Clenching and relaxing the fist does improve the blood flow and makes veins stand out, making it easier to get a sample."

Jackie Hough, president of the National Association of Phlebotomists (NAP), agreed clenching the fist could alter the blood test results.

"But best practice advocates that patients don't tightly clench but gently close their hand during needle insertion and that the hand is loosened prior to the collection of blood.

"Also the tourniquet should not be tightened on the arm for longer than 60 seconds or during the collection of the sample."

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3 comments:

2ndHeartBeat said...

Merv ~

This is new I can use.

As a Heart Tx patient I have had bouts of elevated K+ and then the resulting medication (Kexolate sic?)to reduce the level, this might be a blessing. I have my next round of BT's in 2 weeks and I will not clench my fist and see if it helps.

Thx ~ DAP

Merv Sheppard said...

Another organ recipient called me last night to say he was called by the hospital to quickly fill a prescription for Kayexalate to bring his potassium below safe levels. He said he had used a new lab for the blood work and the tech gave him a rubber ball and asked him to keep squeezing it while she took his blood. Merv.

Gay said...

Clenching the fist prior to phlebotomy is not in compliance with the guidelines issued by Phlebotomists Assoc. of Ireland. See www.pairl.ie We have been campaigning for a number of years to have standardisation of training and certification for all phlebotomists. We have a course leading to National Certificate in Phlebotomy in Ireland now but unfortunately it is not a mandatory requirement.
The hand clenching is only one issue which can alter results. There are a number of practices which can lead to inaccurate results and many phlebotomists, nurses and doctors are unware of them. These are known in the profession as pre-analytical variables and they are highlighted in our guidelines and in the course.
Gay Wright. Chairperson Phlebotomists Association Ciph tutor