Garbage In; Garbage Out: Part III

Over the last few months, Phlebotomy Today-STAT! has been exploring the many ways those who draw and process specimens can unknowingly alter test results. Last month we explored how specimens drawn from vascular access devices become garbage as well as the affect exercise, fist-pumping, posture, and the timing of blood culture collections have on turning specimens—and the results obtained from them—into garbage. (To access this and other archived issues, visit www.phlebotomy.com/PTSTAT.html) This month we will continue with errors committed before the needle is inserted.

Prolonged tourniquet application
As soon as a tourniquet is applied, the blood begins to pool within the veins below the tourniquet. This is what we know as “hemoconcentration.” During this process, large molecules (like proteins and coagulation factors) and cells accumulate in a proportion higher than if the blood was circulating normally. This is due to water migrating into the tissue through the porous capillary beds as the blood pressure below the constriction increases. As a result, specimens drawn from hemoconcentrated veins no longer reflect the patient’s actual status if tourniquet application is prolonged. Therefore, the vein should be accessed within one minute of tourniquet application. If a vein cannot be located and accessed within one minute, the tourniquet should be released, and then reapplied after two minutes.  This allows the blood in the limb to return to a basal state. If it will not jeopardize the draw, the tourniquet should be released as soon as the vein is accessed to minimize the effects of hemoconcentration on the specimen.

Site prep solutions
When cleansing a site with alcohol, CLSI recommends allowing the area to air dry to prevent hemolysis of the specimen.(1) Additionally, some bacteria are killed during the drying process. Therefore, when cleansing with iodine solutions allow the solution to dry and do not retouch the site. Palpating for the vein after cleansing recontaminates the site and risks infection.
         It has been reported that potassium, uric acid and phosphorous are increased when a skin puncture site is prepped with iodine. (2) Other researchers have reported that potassium increases about 25 percent while uric acid decreases 11 percent when venipuncture sites are prepped with an iodine compound.(3) (Unfortunately, this reference is dated and includes a specimen from only one patient.) To avoid iodine contamination, remove it with an alcohol prep, then allow the alcohol to dry before puncturing. No study has documented analyte interference from chlorhexidine preps.

Blood culture contamination
Every hospital struggles to minimize false positive blood cultures. When sites are not cleansed properly or are re-contaminated by palpation after being prepared, the results may incorrectly suggest the patient has a bloodborne bacterial infection, prompting the physician to treat and/or hospitalize a patient unnecessarily.

The following practices will minimize the potential for specimen collection personnel to contaminate blood culture specimens:

• Cleanse the site thoroughly with a friction scrub for at least 30 seconds;
• Allow the antiseptic to dry a minimum of 30 seconds prior to puncture;
• Do not repalpate a cleansed site, not even if you have cleansed the tip of your gloved finger;
• Cleanse the tops of culture vials with an appropriate antiseptic if recommended by the vial manufacturer or if their sterility is in question.
• Fill blood culture bottles before filling tubes for other laboratory tests.

Due to the complexity of human blood and physiology, many factors threaten accurate test results before the specimen is even drawn. All of these factors, individually and collectively, work to change a representative blood specimen into a test result that is no better than garbage to the physician. To make sure the specimens you draw don’t earn you the title of “garbage collector”, adhere to sound specimen collection practices based on the CLSI standards, your facility’s procedure manual, and published studies. When you do, you become part of an elite community of healthcare professionals who safeguard sample quality through all aspects of specimen collection.

Next month: Ways to turn the specimen into garbage while withdrawing the specimen.

References:

1. CLSI. Procedures for the Collection of Diagnostic Blood Specimens by Venipuncture; Approved Standard—Sixth Edition H3-A6. Wayne, PA: Clinical and Laboratory Standards Institute; 2007.
2.  Becan-McBride, K. (ed) Preanalytical Phase and Important Requisite of Laboratory Testing. Advance for Med. Lab. Prof Sept. 28,1998:12-17.
3. Young D. Effects of Preanalytical Variables on Clinical Laboratory Tests. AACC Press. Washington, DC. 1997.

This Month in Phlebotomy Today

Here’s what subscribers to Phlebotomy Today, the Center for Phlebotomy Education’s paid-subscription newsletter currently in its 8^th year of publication, are reading about this month:

• Feature Article: Effects of Pneumatic Transportation on Blood Specimens
• Ask the Lab Guy: Answers to your questions on customer service.
• How do I respond to patient requests I'm not comfortable with?
  
• Phlebotomy in the News: a round-up of articles on phlebotomy and phlebotomists who made Internet headlines in July including these stories:
• Phlebotomist Honored for Saving Patient’s Life
• Hospitals Using Color-Coded Bracelets to Warn Phlebotomists
• Alleged Killer Confesses to Phlebotomist
• Lancets Reused on over 180,000 Patients
• According to the Standards: Drawing from Triple-Lumen Catheters
• Tip of the Month: How Cultured Are You?
• 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: Butterfly Requests

Q: About how long would glucose be stable in a gel barrier tube that was centrifuged and stored for six days? Some here are arguing the gel barrier protects the glucose; I think that the glucose leaches into the gel, causing a falsely low result. Can you provide me with the proper info and a reference?

A: According to CLSI, serum stored on top of gel is stable for 2-5 days.(1) Another source indicates that plasma stored on gel separator barriers show a decrease in glucose concentration from 9% on day 1 to 12% on day 7.(2)

References:

1. NCCLS. Procedures for the Handling and Processing of Blood Specimens— Approved Standard, H18-A3 Wayne, PA, 2004.
2. Madira WM, Wilcox AH, Barron JL. Storage of plasma in primary plasma separator tubes. Ann Clin Biochem 30; 213-214

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.

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 "Accurate Results Begin With Me!^® t-shirt. The exercise will conclude with a review of the selected submissions and a discussion of the standards pertinent to the case study

Many PT-STAT! subscribers related to this month’s scenario; one admitted it happens at her facility at least once a week. As such, there was no shortage of creative responses. The most common resolution proposed was for the phlebotomist to find a coworker to occupy the children so the draw could go smoothly and without interruption (44%). A typical response for this kind of approach went like this:

“I would go get another Phlebotomist or staff member to watch the children while I draw the patient. I would ask our staff to take them into the outpatient draw room that has a bed, ask them to sit on the bed and engage the children by asking them questions and give them some stickers.”

Twenty-five percent of respondents said they would ask the mother to control her children or request she return after arranging childcare. A typical response in this category went like this:

“I would explain to the patient that the blood drawing area is an area of considerable risk and I would not want anything to happen to any of her beautiful children. I would kindly but firmly tell her that if her children can not be quiet and still, she will have to return at a different time for her blood draw, either without the children or when she is accompanied by someone who can stay with them in the waiting area while the venipuncture is performed.”

We particularly liked the responses from those who would turn the situation into a learning experience for the five inquisitive children. Even though only 12% of respondents were brave enough to think about converting the outpatient drawing area into a classroom, we thought it was a commendable intention. Our favorite response comes from Christine S.:

“The first thing is to address the children before drawing or even attempting to draw the blood. I explain to them what I am about to do for their Mom. I show them the tubes and the unopened needle. I even explain about the tourniquet. They will be told it is something very important for their Mommy and needs to be done perfect. It won't hurt and it isn't scary. But Mommy's chair should not move or be bumped.

“We have coloring books in our lab. I will offer them a choice; you can either color in our coloring book, or you can all stand here quietly by the curtain, and watch what I am doing. Most children want to watch and are quite cooperative. If it turns out the children will not listen to my choices, I will address it with my patient. I will explain very nicely, that I need to be able to concentrate completely on drawing blood, and could she tell her children to go to the waiting area by the curtain. I am the Lab Assistant supervisor in a hospital. On a fully staffed day, I can always ask one of my employees to entertain the children while I draw the blood, or I can do the entertaining part, and they draw the patient. Team work is always most helpful. If that doesn't do the trick, I can suggest the patient come back without her children.”

For her comprehensive and educational approach to this month’s case study, Christine will receive a free "Accurate Results Begin With Me!"® t-shirt.