Quality collection: the phlebotomist's role in pre-analytical errors.

Medical error has been defined as a "failure to process." (1) The ultimate consequences of pre-analytical errors introduced during the specimen-collection process span a broad spectrum of negative outcomes. For the patient, these outcomes range from no detected harm to death. When patient blood specimens are required for examination, the collection process demands the knowledge and skills of a competent phlebotomist. From receipt of the physician's order until examination of the specimen begins, the phlebotomist is often the primary guardian of specimen quality.

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Unfortunately, in today's various healthcare settings, the role competent phlebotomists play in assuring specimen quality has been undervalued. Evidence that their role is underestimated includes:

* disregard among other healthcare professions for the complexity and invasive nature of phlebotomy procedures;

* decentralization of phlebotomy services:

* lack of nationally established minimum training and/or certification requirements for those assigned blood collection responsibilities; and

* lack of emphasis on, or access to. phlebotomy continuing education.

Here, we explore some of the critical concepts all specimen-collection personnel must master in order that physicians are not misled by laboratory results which constitute 70% of the objective information they receive on their patients' status. Strict adherence to blood-collection procedures is the most effective means to ensure specimen quality during the collection and processing phases of laboratory testing. Studies show up to 56% of laboratory errors occur during the pre-analytic phase of testing. (2) The expertise of the collector, therefore, is a pivotal link in the laboratory's chain of total quality-management activities.

Patient identification

The most potentially fatal pre-analytical error is improper patient identification. This is basic but bears mentioning. Failure to properly identify patients can lead them to be treated, diagnosed, medicated, and managed according to another patient's health status.

According to the Clinical and Laboratory Standards Institute (CLSI, formerly NCCLS) an inpatient should be asked to state her full name, address, birth date, and/or unique identification number. The information provided must be compared with the information on the identification bracelet, which must be attached to the patient, and the test requisition or computer-generated labels brought to the bedside. All discrepancies must be reported to the appropriate caregiver according to facility policy and resolved before collection.

What if the patient is unable to speak her name due to language barriers or the patient's state of consciousness? The standards require a caregiver or family member provide the information on the patient's behalf before drawing the specimen. (3) This requirement is justified in part by studies that show up to 16% of identification bracelets contain erroneous information. (4) Documenting the name of the verifier is good risk management.

Emergency-room patients should be tagged with some sort of identification even if it is only a temporary number. The following items are not acceptable substitutes for an identification bracelet:

* charts on the wall;

* water pitchers;

* bed tags; and

* identification bracelets not attached to the patient.

There is no substitute for either having a hard identifier attached to the patient, having the patient speak her name, or having a caregiver verify the patient's identity.

For outpatients, CLSI recommends having the patient state her name address, birth date, and/or unique identification number and comparing that information with the requisition or forms the patient brings to the draw station. Neither inpatients nor outpatients should be asked to affirm their name as in "Are you Jane Doe?" Patients who may be hard of hearing might misunderstand and respond "yes" just to be polite. A wiser solution is to ask the patient to tell you her name.

Special-collection requirements

Special testing requirements must be met prior to collection. Fasting specimens must be collected after a 10- to 12-hour complete dietary restriction of everything except water and medications. Although fasting for glucose must be overnight, studies show the difference between an overnight fast and a six- to nine-hour daytime fast for lipids is not clinically significant. (5)

Because of the threat over- or under-medication can have on the patient, strict adherence to the timing of therapeutic drug collections is imperative. Likewise, requirements that the patient be recumbent must be met in order for the physician to properly manage the patient's health. Regular reviews of the laboratory's test requirements help specimen-collection personnel remain mindful of time- and posture-dependent tests.

Collection restrictions

Few therapies threaten accurate blood-test results more than the infusion of intravenous fluids. CLSI and most textbooks recommend avoiding draws from the same arm as an active IV unless absolutely necessary. If unavoidable, CLSI recommends having the nurse or appropriate caregiver shut off the IV for two minutes, apply the tourniquet below the infusion site, and withdraw the specimen below the tourniquet. Some authors recommend discarding the first 5cc (cubic centimeters) of blood if possible. (2,6) Document the arm from which the specimen was collected as well as the fact that it was drawn below an infusion site.

Drawing above an IV that has been temporarily shut off is discouraged due to the potential for analyte contamination.3 Drawing blood at the same time that dyes for radiological procedures are being or have been recently infused should be avoided if possible.

Neither venipunctures nor skin punctures should be performed on the affected side of patients who have had a prior mastectomy. (3,7) Not only is there a risk of fluid imbalance in the affected limb, which can lead to erroneous results, the procedure puts the patient at risk of painful short- or long-term lymphedema.

Site preparation

Specimen collection personnel should also avoid sites that appear infiltrated, infected, edematous, or burned--not only to protect the patient from further complications but also to safeguard against collecting specimens that could be altered by the condition. CLSI advises against drawing arterial specimens as a substitute for venous blood when veins are difficult to locate.

The best way to ensure a successful capillary collection is to pre-warm the intended puncture site for three to five minutes. Applying a commercial infant heel warmer or warm compress not exceeding 42[degrees]C to the skin increases blood flow to the area up to sevenfold. (7) Taking the time to perform this step promotes higher quality specimens because the blood is obtained more quickly and with less tissue compression.

For routine venipuncture and capillary collections, cleansing the site with 70% isopropyl alcohol is sufficient. Allowing the site to air dry improves the alcohol's antiseptic effect, as well as prevents hemolysis and contamination of the specimen that residual alcohol can cause. (7) For capillary lead levels, a thorough scrub with soap and water of the finger and nail area may be required.

For blood cultures, the probability that a positive blood culture represents infection rather than contamination is a function of the effectiveness of skin antisepsis at the time of the venipuncture. Growth of skin contaminants may not only be confusing to clinicians but also can be expensive for both the patient and the institution. (8) The traditional recommendation for skin preparation has been the application of 70% alcohol followed by or in conjunction with a 30- to 60-second friction scrub. Apply chlorhexidine, povidone-iodine or 2% iodine tincture, and allow to air dry. For infants above two months of age, and for patients with iodine sensitivity, chlorhexidine gluconate is recommended.3 Regardless of the type of skin preparation used, meticulous care and aseptic technique are essential to reduce contamination. Studies have shown that a dedicated blood-culture team and/or phlebotomists are less likely than other healthcare workers to contaminate blood-culture specimens. (8)

Collection technique

The phlebotomist's ability to select the appropriate supplies and equipment for each draw, based on an assessment of the patient and specimen test requirements, is crucial to assuring a successful collection. Equipment and supplies should be checked for acceptable expiration dates and sterility, as appropriate.

When collecting capillary specimens, proper positioning of the finger or heel will enhance blood flow. To minimize the risks of tissue fluid contamination and hemolysis, the collector should wipe away the first formed drop of blood and avoid exerting excessive pressure to the surrounding tissue. When more than one micro-collection tube is required, the order of draw for capillary collections as established by CLSI should be followed. (7) To prevent the formation of platelet clumps, microcollection tubes containing EDTA should be collected first, followed by other-additive tubes and then non-additive tubes. Additive tubes should be mixed periodically during collection, according to the tube-manufacturer's instructions. Once the appropriate volume of blood has been obtained, tubes should be immediately capped and the blood mixed well by gentle inversion.

The appropriate number of test circles on newborn screening cards should each be filled with one well-formed drop of blood that saturates the filter paper front to back. Care should be taken not to press the filter paper against the infant's heel. Any technique that might scratch, compress, or indent the paper's fibers should not be used.

Hemolysis is the most common reason laboratories reject specimens. (2) During venipuncture, rupture of red blood cells may occur for several reasons, including use of small bore needles (i.e., 25-gauge), excessive pulling pressure on the syringe plunger, poor needle placement within the vein resulting in a slow draw, and aggressive mixing of the sample. To minimize the effects of hemoconcentration during collection, the tourniquet should be released as soon as possible after blood flow is established. Because vigorous hand-pumping may also alter the concentration of certain analytes in the blood, this practice should be discouraged.

For venipunctures, unless otherwise established by facility protocol, tubes should be collected following the order of draw established by CLSI in 2003 to prevent additive carryover.3 Additive carryover cannot be detected by the laboratory and, as a result, may lead to disastrous consequences for the patient when medical decisions are based on altered results. It is imperative all additive tubes be filled in the proper order and adequately mixed according to the tube manufacturer's instructions. Collection tubes should be available in a variety of sizes to ensure minimum fill requirements are met when presented with difficult or pediatric draws. According to CLSI, the order of draw is as follows:

1. Blood-culture tubes;

2. Sodium-citrate tubes (e.g., blue stopper);

3. Serum tubes with or without clot activator, with or without gel separator (e.g., red, gold, speckled stopper);

4. Heparin tubes with or without gel (e.g., green stopper);

5. EDTA tubes (e.g., lavender stopper); and

6. Glycolytic inhibitor tubes (e.g., gray stopper). (3)

Underfilling of additive tubes alters the desired blood-to-anticoagulant ratio and, in the case of EDTA tubes, causes red-blood-cell shrinkage. An underfilled sodium-citrate tube will produce a falsely lengthened aPTT result.2 Manual filling of additive tubes should also be avoided.

When using a winged blood-collection set, a discard tube must be used to prime the tubing when a coagulation tube is the first or only tube drawn. For blood cultures, if both anaerobic and aerobic bottles are included in the set, the aerobic bottle should be filled first, to remove air from the tubing. Underfilling of blood-culture bottles may result in failed recovery of organisms present in small quantities, whereas overfilling of blood-culture bottles may elicit a false-positive result during incubation. (2) In any case, improperly filled additive tubes and culture bottles may result in specimen rejection or, if tested, yield inaccurate results that jeopardize patient care.

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Collections from vascular access devices (VADs) should be avoided since they pose an increased risk of contamination by intravenous fluids and exhibit a higher rate of hemolysis compared to venipuncture. (2) It has also been shown that blood cultures collected from VADs are more likely to be contaminated than those obtained by venipuncture. (8) When warranted, a healthcare professional trained in IV management should perform the draw and include a 5-cc discard.

Specimen labeling

To prevent specimen mix-up or rejection, specimens should be properly and permanently labeled at the patient's side, bearing at least the following:

* the patient's first and last names;

* an identification number;

* the date;

* the time (as required); and

* the collector's identification. (3)

If a bar-coding system is used, facility protocol should be followed.

Specimen handling and processing

Because improper handling and delays in specimen processing can compromise specimen integrity and result in erroneous test results, the phlebotomist must transport specimens in an appropriate and timely manner, according to the facility's established protocol. A working knowledge of analyte stability is necessary for specimen processing and in evaluating requests for additional testing of a previously collected specimen.

To prevent excess agitation of tube contents that could induce hemolysis, filled collection tubes should be transported in an upright position whenever possible. Pneumatic transport systems should be evaluated to determine which analytes are affected during transport. The temperature at which specimens are transported may also compromise analyte stability. Unless collection protocol requires chilling of the specimen (e.g., renin, ammonia, and so on), specimens should be transported at room temperature (22[degrees]C to 25[degrees]C). Because of the deteriorating effects of light on photosensitive analytes, such as bilirubin, steps must be taken to protect such specimens from light exposure.

Newborn-screening specimens should be protected from potential sources of contamination (i.e., direct contact with other blood spot specimens, sprays, lotions, glove powder, and so on) while allowed to air dry on a flat surface for a minimum of three hours. Exposure to direct sunlight and environmental extremes, such as heat and humidity, should also be avoided. (9)

Serum specimens should be allowed to fully clot prior to centrifugation. For optimal specimen quality, serum or plasma should be separated from specimens as soon as possible unless there is evidence that the analyte(s) requested will be not be affected by prolonged exposure to cells. Calcium, glucose, LDH, and potassium are some analytes that change significantly when serum or plasma is kept in contact with cells beyond two hours (see Figure 1). (10) Generally, chemistry specimens should be centrifuged and separated within two hours of collection. (10) Tubes should remain closed until time of testing to prevent evaporation.

Coagulation specimens to be tested for aPTT can remain at room temperature after collection, but should be tested within four hours in order to be reliable. (11) When testing patients on unfractionated heparin, specimen processing personnel should centrifuge the specimen, remove the plasma from the cells within one hour and perform the test within four hours of collection.

Prothrombin times are more forgiving and remain stable for up to 48 hours at room temperature, even uncentrifuged, as long as the stopper has not been removed. (11) If the tube is refrigerated, however, the PT results have been shown to increase after seven hours. (12) Freezing citrated plasma has been shown to effectively preserve PT and PTT results up to 21 days at -70[degrees]C.

The phlebotomist's role in the workplace

In an age of technological advancement, phlebotomy remains a manual procedure, requiring critical decisions and human skills that will never be automated. The competent phlebotomist recognizes and prevents pre-analytic variables that may introduce error, fulfilling a vital role in the laboratory's quality-management system. Because diverse interactions and specialized knowledge are required, the phlebotomist profoundly impacts patient care, patient relations, and the accuracy and efficiency of the laboratory's path of workflow. Facilities striving for excellence in these areas should begin by examining the value they place on the phlebotomist's role in the workplace. After all, that is where quality collections begin.

Dennis J. Ernst MT(ASCP) is the Director of the Center for Phlebotomy Education and has participated in the revision of several CLSI specimen collection standards. Lisa 0. Ballance, a regional laboratory improvement consultant with the North Carolina State Laboratory of Public Health in Raleigh, NC, served on CLSI's Skin Puncture Subcommittee for the NCCLS H4-A5 standard approved in June 2004, was the event organizer for the inaugural North Carolina Clinical Lab Tech Dayeducational conference in 2005, and is the course director for the North Carolina Public Health Phlebotomy Initiative.

References

1. Clinical and Laboratory Standards Institute. Application of a Quality Management Model for Laboratory Services. Wayne, PA: NCCLS. 2004. Approved Guideline, GP26-A3.

2. Ernst, D. Applied Phlebotomy. Philadelphia, PA. Lippincott Williams & Wilkins, 2005.

3. Clinical and Laboratory Standards Institute. Procedures for the Collection of Diagnostic Blood Specimens by Venipuncture. Wayne, PA: NCCLS 2003. Approved Standard, H3-A5.

4. Paxton, A. Stamping out Specimen Collection Errors. CAP Today. May 1999.

5. Baer D, ed. Tips from the Clinical Experts. MLO 2005;37(8):36.

6. McCall R, Tankersley C. Phlebotomy Essentials. 3rd Ed. Baltimore, MD: Lippincott Williams & Wilkins; 2003.

7. Clinical and Laboratory Standards Institute. Procedures and Devices for the Collection of Diagnostic Capillary Blood Specimens. Wayne, PA: NCCLS 2004. Approved Standard, H4-A5.

8. Murray, PR, ed. Manual of Clinical Microbiology, 8th ed. Washington, DC. ASM Press, 2003;185-205.

9. Clinical and Laboratory Standards Institute. Blood Collection on Filter Paper for Newborn Screening Programs. Wayne, PA: NCCLS, 2003. Approved Standard, LA4-A4.

10. Clinical and Laboratory Standards Institute. Procedures for the Handling and Processing of Blood Specimens. Wayne, PA: NCCLS, 2004. Approved Guideline, GP18-A3.

11. Clinical and Laboratory Standards Institute. Collection, Transport, and Processing of Blood Specimens for Testing Plasma-Based Coagulation Assays. Wayne, PA: NCCLS, 2003. Approved Standard, H21-A4.

12. Narayanan S. The preanalytic phase an important component of laboratory testing. Am J Clin Pathol 2000; 113:429-452.

Figure 1. Analytes that are affected by prolonged exposure to red blood
cells:

  * APTT
  * Bicarbonate
  * Calcium
  * Chloride
  * Glucose
  * HDL cholesterol
  * Iron
  * Lactate dehydrogenase (LDH)
  * Magnesium (ionized)
  * Phosphorous
  * Potassium