Top Ten Ways Blood Potassium Can Be Altered During and After the Draw

Few components of the blood are as vulnerable to blood collection, handling, and processing (preanalytical) technique as potassium is. In fact, Young's Effects of Preanalytical Variables on Clinical Laboratory Tests lists over 50 preventable preanalytical conditions that cause a potassium level to be falsely elevated. Do you contribute to inaccurate potassium results when you draw, transport, handle, or process blood samples? Critique yourself with this list of common errors that can lead patients with normal potassium levels to appear elevated, and patients with dangerously low levels to appear normal:

10. Recentrifugation — spinning gel tubes a second time has been found to increase the potassium level by 47%.

9. Inadequate centrifugation — without enough g-force, platelets can remain in the serum. Because platelets release potassium, they can contribute to the concentration in the serum to be tested, presenting an erroneous impression to the physician of the patient's physiology.

8. Spinning tubes with stoppers off — this technique has been shown to increase potassium levels in the specimen to be tested by 135 percent.

7. Pouring blood from one tube to another — pouring contents from an EDTA tube into a tube to be tested for a profile that includes potassium is like spiking it with pure potassium. Okay, that's an exaggeration, but still. It's a really, really bad idea.

6. Delayed centrifugation — red cells, which have 25 times as much potassium as the serum or plasma they're swimming in, will leak K+ once they leave the body. Within two hours, the serum/plasma in the tube is significantly higher in the electrolyte than what's really in the patient.

5. Chilling tubes before centrifugation — the mechanism that keeps potassium inside the red cells slows to a crawl at chilled temps. Refrigeration is for vegetables, not blood that will be tested for potassium unless the serum or plasma has been separated from contact with the cells.

4. Hemolysis — red cells are rich in potassium. When they rupture because of poor collection or handling techniques, it adds to the total concentration in the serum or plasma to be tested and reported.

3. Incorrect order of draw — when filling EDTA tubes before filling tubes to be tested for K+, enough blood can carry over by the needle that pierces the stopper to spike the potassium to grossly distorted levels.

2. IV contamination — many IVs infuse potassium. When drawing from a vascular-access device or above a temporarily discontinued IV, you risk contaminating the sample with enough residual K+ to confuse the physician.

1. Fist pumping — having your patient pump his/her fist to make veins more pronounced can increase potassium levels up to 20%. That's enough to push a normal level into a panic range, or spike life-threateningly low potassiums into a normal range. Fist pumping in patients has been reported to be responsible for one-third of all elevated potassiums, and half of those that require immediate physician notification.

Consider potassium to be your problem child that insists on running wild. Controlling its behavior takes discipline and a consistent application of the rules of blood sample collection and processing. Take a time out and make sure these top ten threats to accurate potassium results don't cause your patients' potassiums to run amok.

This Month in Phlebotomy Today

Here’s what subscribers to Phlebotomy Today, the Center for Phlebotomy Education’s paid-subscription newsletter currently in its 10^th year of publication, are reading about this month:

• Feature Articles: Career Ladder for Phlebotomists,
         Are You Career-Ladder Material?
  
• Phlebotomy in the News: a round-up of articles on phlebotomy and phlebotomists who made Internet headlines in June including these stories:
• Phlebotomists Using Barcode Scanners 20% More Productive
• Phlebotomist Gets 18 Months for Molesting Patient
• Phlebotomist Resigns after Being Ordered to Remove Crucifix
• Phlebotomist Competes for Miss Deaf Utah
• Device Notifies Healthcare Workers When Hands Need Washing
• Australian Healthcare Workers Urged to Adhere to National Hand Hygiene Initiative
• European Union Considering Safety Needle Legislation
• According to the Standards: Infant fingersticks
• Tip of the Month: Mind the Gap
• CEU questions (institutional version only).

Buy this issue for only $9.95.

For subscription rates and to subscribe to Phlebotomy Today, visit www.phlebotomy.com/PhlebotomyToday.html. The current month’s issue will be emailed to you immediately upon subscribing.

Featured FAQ: Discard tube

Q: There’s a lot of confusion at our facility about when we need to draw a discard tube. Can you clear this up for us?

A: The practice of withdrawing and discarding a portion of blood before filling a coag (blue-top) tube is old school. Truth be told, tissue thromboplastin, long thought to accumulate in the needle during the venipuncture, has never been proven to alter coag results. In fact, many studies have shown that if the citrate tube is the first tube drawn, protimes and aPTTs are not affected.

The recommendation for a discard tube was dropped in 1998 when the CLSI, the agency that establishes the standards for blood collection procedures, determined that there was insufficient evidence to support the practice. However, they still recommend it under two circumstances: 1) whenever specific factor assays are drawn such as Factor VIII; and 2) if you are drawing through a butterfly set. No studies have been attempted to determine whether or not tissue thromboplastin affects special factor assays. So CLSI suggests facilities establish their own protocol for such tests.

When using butterfly sets, you should apply a discard tube long enough to evacuate the air from the tubing so that the patient's tube filled isn't underfilled. It doesn’t have to be filled. Then apply the tube to be tested. Blue top tubes must be filled at least 90% of their volume in order for the coag studies to be accurate. There isn't much leeway.

Each month, PT-STAT! will publish one of the hundreds of phlebotomy FAQs in the growing database of questions and answers available in Phlebotomy Central, the members-only section of the Center for Phlebotomy Education's web site. For information on joining Phlebotomy Central, visit www.phlebotomy.com/PhlebotomyCentral.html.

Survey Says: Where Would You Seek Inpatient Services?

Our latest survey asked Phlebotomy Today STAT! readers: If given a choice, would you seek inpatient services at your employing institution for you or a loved one as opposed to elsewhere. Why?

Over 81% of those responding would have themselves or their loved ones treated at their facility. Eighteen percent would not. Some comments:

• Just depends on what was being done.
• I know our strengths and weaknesses. I know how much everyone cares.
• I'm not only proud to work here but I trust the people in all the various departments that work here. I do seek service here for myself and my family. I wouldn't go anywhere else!
• Across our institution, we hold ourselves to the highest standards. I have been an inpatient and had nothing but praise for my caregivers.
• I have been in the healthcare field for 14 years, and I have always said that I may not know which hospital/physician to choose, but I know which one NOT to choose.
• I know the staff.
• By staying at our hospital, at least you know what to expect even if it's not the greatest.
• I work in a children's hospital and I consider our phlebotomists here very caring and understanding and know how to obtain samples from the smallest veins.
• The in-house phlebs do not have the experience that those of us have in the outlying areas. They use mainly new trainees. Not a good thing for them to practice on people.
• We have adequate resources available to receive good care. I have faith in my employer's abilities versus the competition.
• No. Mainly because of gossip and lack of quality physicians and nurses.
• We simply offer the best care in our service area.
• I would feel more comfortable at an employing institution, because I would know the employees and that will reduce the stress.
• Yes, since I would be drawing the blood.
• Although no place is perfect, I know how hard our facility works to give the very best to all patients.... We are faith-based institution and have the freedom to bring that to our work.
• I happen to work at a well respected state-of-the-art hospital in the northwest. I would have my family receive services here undoubtedly.
• I see what really goes on behind the scenes and it may not be yourself that don't (sic) have good work ethics, but a coworker, and if it is happening on a regular basis you or your family won't be any different.
• Yes, I would. I believe I would receive very good care. I trust the staff at our facility.
• I am very comfortable with my co-workers and have faith in my employer and the physicians and nurses. We are a "patient-oriented" establishment and I do see that as such from the majority of the staff.
• I have been employed at the same local hospital for seventeen years. I have chosen to stay not only because of my work environment, but also because of my employer's dedication to compassionate, high quality healthcare. I refer my friends and family with confidence.
• Our hospital IS the best in the area. I have been an inpatient here as well as had family in three other hospitals in close proximity and our hospital's technology, facilities and compassionate staff (in all areas) make our hospital my first choice. Our upper management works hard to maintain a caring culture here and is always finding ways to improve employee and patient satisfaction.
• I have seen the staffing situation here and since this is the "charity" hospital in my city I think that the more "elite" hospitals in town have more staff so they have the ability to "look better" in the eyes of the public.

Overwhelmingly, survey participants expressed a vote of confidence in the quality of care their employing institutions provide. Recurring themes echoed among respondents who would seek medical care for themselves or their loved ones in-house were: 1.) the level of caring shown by the facility, 2.) the faith and trust they place in the employer and staff, and 3.) the high standards and level of care maintained. For the majority, the “insider knowledge” that comes with being an employee was a plus for the employer. For the 18% who would not seek inpatient services at their employing institution, find out where the other 81% work.

This month’s survey question: In your facility, is phlebotomy centralized ( i.e., phlebotomists perform all routine blood collections) or decentralized (e.g., staff of various disciplines are cross-trained to draw blood)? Click here to participate in the survey.

Featured Product: Blood Specimen Collection FAQs

What Would You Do?

Each month, What Would You Do? presents a different case study, then asks readers to contribute their ideas as to how each situation would best be handled. The following month, selected responses will be chosen by the editor and published (sender will be identified by first name and state only). The most accurate, well written response will receive a free download from the Center for Phlebotomy Education’s To the Point® library of articles. The exercise will conclude with a review of the selected submissions and a discussion of the standards pertinent to the case study.

Surprisingly, there were a wide variety of responses to this month's case study considering the risks of drawing above an IV and violating facility policy. Although the CLSI standards leave it up to the facility to establish a policy for drawing above active IVs, it clearly defines the perils. Testing for the same analytes being infused (e.g., sodium, potassium, glucose, etc.), adding orders for more tests on samples previously drawn above an IV are just two examples. While forty-two percent of those who responded said they'd draw above the IV at the nurse's request, only half of those said they'd document the circumstances; none indicated they'd make a notation on the sample itself, which is required by the CLSI standards in its last revision (2007) whenever drawing above or below an IV site.

Thirty-five percent said they would flat-out not draw the specimen because it's against facility policy regardless of pressure to do so. One respondent, a nurse and IV therapy manager, put it quite succinctly: "An individual nurse is not authorized to change policy." Fifty-seven percent indicated they would notify their supervisor or the physician before breaching the policy. (Total percentages exceed 100% due to some responses that fell into multiple categories.)

Bill from Ohio suggests having the physician order the blood to be drawn above the IV in writing to force a review of facility policy. In his words, "caution should be the key word, making sure that drawing from this site would not adversely affect the results of any testing."

Another reader, DeEtte of Michigan, shared a similar scenario that happened to her:
"As a phlebotomy supervisor, this happened to me one day when I was rounding with my day shift staff.  There was a patient who had an IV in his right hand and a fistula in the left arm.  I told the patient I was not able to draw above his IV and the patient got upset and started yelling at me because 'everyone else had'.  I apologized to the patient and went on to the next room.  The patient's nurse came to find me and started yelling at me in front of another patient that I needed to 'get back there and draw it above the IV.'  I asked the nurse to come to the hall to discuss the matter out of patient earshot and I proceeded to tell her the results would be negatively impacted if drawn above the IV, even if the IV was shut off.  The nurse did not want to hear it, wrote my name down and I calmly continued my draws.  When I returned to the lab I called the nursing supervisor for that floor and explained the situation.  The nursing supervisor agreed to get an order for a foot draw for that patient and apologized.  I researched to see if indeed I did have a phlebotomist who had drawn this patient above their IV and the patient had not had any lab draws so I was confident my staff had not gone against policy and drawn this patient above their IV." We like the calm, professional manner in which she handled the situation.

Seven percent said they'd draw from below the IV. The most surprising response came from the seven percent who said they'd draw from an artery. Surprising because arterial sticks as an alternative to venipunctures are a clear deviation from the CLSI standards. Not only do arterial punctures put the patient at increased risk of injury (and litigation since the standards so clearly advise against arterial draws as a venipuncture alternative), the composition of arterial blood is not equivalent to venous blood for many analytes.

We also liked the response from Elana, a nurse from Arizona:
"If I am unable to find a vein on an ICU patient with an active IV infusion and the patient's nurse is telling me to draw above the IV after she shuts off the line, I would seriously question the competency of that nurse. Performing venipuncture proximal from an infusion site has potential to cause extravasation when the infusion is restarted. Depending on what solution is being infused, this could be very harmful to the patient.

"If it is NOT against hospital policy to draw from the IV, proper procedures may be taken to discontinue the infusion, flush with appropriate amount of saline, and draw off appropriate amount of 'waste' prior to drawing specimen, being sure to adhere strictly to hospital policy. If drawing from an infusion IV is prohibited, keep searching for veins, take actions like applying a warm compress, dangle the extremity... don't attempt the stick if you can't find a vein and seek assistance from a more expert phlebotomist."

For their articulate responses and legitimate solutions to last month's case study, both DeEtte and Elana will each receive a free download from the Center for Phlebotomy Education’s To the Point® library of articles.