"Q&A" editor’s note: A laboratory specialist asked the CAP to indicate
whether a specified manufacturer’s urinalysis microscopic examination
system met CAP approved procedural standards. Questions of this type are
periodically submitted to "Q&A" and the CAP Laboratory Accreditation Program.
The CAP’s position on whether an instrument or procedure is acceptable
under CAP standards is outlined in the response by Edward J. Gruber, MT
(ASCP), and reflects the views of this editor.
A. The College does not endorse instrumentation or procedures.
The CAP’s philosophy is that a laboratory director should be responsible for
evaluating the appropriateness of laboratory instruments and establish and monitor
the standards for performance and quality control. Alternative quality control
systems, such as electronic QC or internal QC, must be evaluated on-site by
the laboratory director to verify that they are scientifically valid and function
effectively based on the data from the manufacturer and their own internal validation
studies. CAP policy states, "The Commission on Laboratory Accreditation does
not evaluate instruments, devices, materials, or other laboratory systems with
respect to whether or not such items satisfy the standards for laboratory accreditation."1
The inspection checklists contain guidelines that inspectors use to verify
that laboratories are meeting the CAP’s standards for laboratory accreditation.
The checklists also contain notes, commentary, and references that laboratories
may use in evaluating new instrumentation and establishing quality control protocols
and procedures. The checklists are sent to laboratories prior to their inspection
and self-inspection and are available on the CAP’s Web site.
The College also welcomes the opportunity to discuss checklist question interpretation
with laboratories on an individual basis. Technical assistance is available
to LAP participants at 800-323-4040 ext. 6065.
1. Commission on Laboratory Accreditation Policy Manual.
Northfield, Ill.: College of American Pathologists; 1994:Policy 5.01a.
Edward J. Gruber,
Technical specialist II
CAP Laboratory Accreditation Program
Q. In our performance improvement efforts in the laboratory, we are
continually monitoring percentages of specimens that demonstrate significant
hemolysis. This has been a particular issue for nurse draws received from the
emergency department. We have been unable to find in the literature a threshold
of minimal percentage of specimens that should show hemolysis. Can you comment?
A. Hemolysis, or the degradation of red cells in clinical blood
samples, may alter laboratory-generated analytical results1and thus
might necessitate repeat collection by phlebotomy. The rate of hemolysis will
vary among institutions and is dependent on two important factors: the phlebotomists’
background and the method used for specimen collection.
Some hospitals have successfully implemented patient-focused care, which is
a team-oriented approach to health care delivery.2-4The primary goal
is to promote quality and customer satisfaction that is measured more by the
patient’s standards than the caregiver’s standards.2-4The overall
strategy is to increase the time nursing staff spends in patient care and to
decrease the number of employees who have contact with a patient.
A major disadvantage to this approach is the lack of educational institutions
providing a curriculum that focuses on all of the responsibilities of a patient
care technician, including phlebotomy, ambulation, point-of-care testing, physical
therapy, and occupational therapy. For example, Evans describes how the typical
six-week-long laboratory phlebotomy training program had to be reduced to three
weeks and then to 80 hours if adult patients only were to be drawn, with the
addition of 40 hours if pediatric patients were included.5
Authors have reported an increase in unacceptable specimens, including hemolysis,
after implementing a patient-focused care program.6,7 The specimen-rejection
rate rose from an average of 210 specimens per month to 300 specimens per month
after nurses and clerks started performing phlebotomy.6 After nurses
performed phlebotomy, programs reported a 50 percent reduction in stat laboratory
requests and a significant increase in unacceptable specimens.7Adequate
initial training and retraining, if necessary, are important elements of the
vigilance system required to maintain quality when using part-time phlebotomists.
A blood specimen may be collected with a syringe or an evacuated tube system
directly from the vein or from an intravenous catheter. The literature indicates
that registered nurses prefer to draw blood from an intravenous line.8,9
Hemolysis is a common complication when blood is drawn from an intravenous catheter—it
may occur at a rate ranging from 42 percent for Teflon catheters to 55 percent
for Vialon catheters, depending on the material used to manufacture the intravenous
catheter.9-12 The frequency of hemolysis may be reduced to 12 percent
when a stainless steel needle is used.12 Kennedy et al reported a
significant (P=0.03) reduction in hemolysis when blood was drawn through
a 21-gauge needle into vacuum specimen collection tubes (3.8 percent), compared
with 13.7 percent when blood was collected through intravenous catheters ranging
from 24-gauge to 14-gauge into a syringe. In general, the smaller the intravenous
catheter diameter, the higher the rate of hemolysis secondary to increased shear
The rate of hemolysis varies, therefore, with the degree of phlebotomy training
and the method used to collect the blood specimen. The range varies in the literature
from 3.8 percent for a 21-gauge needle into vacuum specimen collection tubes
to 100 percent when a 24-gauge intravenous catheter is used.9 The
rate of hemolysis in one study varied from 12.4 percent for emergency department
personnel versus 1.6 percent for laboratory personnel.14 A change
in phlebotomy practice should be closely monitored for a change in the rate
of hemolysis—for example, the combination of drawing blood from newly
placed intravenous catheters into vacuum specimen collection tubes and the introduction
of a whole blood electrolyte method (i-Stat, Abbott, Bedford, Mass.) masked
a potassium abnormality.
Because it is impossible to visually inspect a whole blood specimen for hemolysis,
we have introduced a centrifuge to spin down the cells to facilitate visual
inspection of plasma. In this case, the plasma revealed hemolysis and the hemolysis-free
serum sample demonstrated hypokalemia in the presurgical patient. A marked reduction
in the rate of hemolysis was observed after a vacuum specimen, which has less
vacuum and thus is only partially filled, was introduced to remove blood from
the intravenous catheter.
1. Young DS. Hemolysis. In: Effects of Preanalytical Variable
on Clinical Laboratory Tests. 2nd ed. Washington, DC: AACC Press; 1997:(4)228-234.
2. Lark S. Patient-focused care. Is it working? Is it here
to stay? Laboratory Medicine. 1997;28:644-651.
3. Murphy R. Work re-engineering: the benefits and the barriers,
an analytical review. J Soc Health Syst. 1994;5:73-84.
4. McQueen J. Overcoming the barriers to implementing patient-focused
care. Journal of Healthcare Information Management Systems. 1993;7(2):17-21.
5. Evans VJ. The laboratory in a restructured environment.
In: Parsons ML, Murdaugh CL, eds. Patient-Centered Care. A Model for Restructuring.
Gaithersburg, Md.: Aspen Publishers; 1994: 435-453.
6. Gable JT, Pyevac ZP. Paradigm shift: phlebotomy belongs
to nursing. Clinical Laboratory Management Review. 1995; 9: 286-297.
7. Marchwinski J. Transferring inpatient specimen collection
to nursing: the multidisciplinary path to success. Clinical Laboratory Management
Review. 1997; 11: 368-373.
8. Eyherabide A. Intermediate care/telementary case study.
In: Parsons ML, Murdaugh CL, eds. Patient-Centered Care. A Model for Restructuring.
Gaithersburg, Md.: Aspen Publishers; 1994: 362-384.
9. Kennedy C, Angermuller S, King R, et al. A comparison of
hemolysis rates using intravenous catheters versus venipuncture tubes for obtaining
blood samples. Journal of Emergency Nursing. 1996;22:566-569.
10. Herr RD, Bossart PJ, Blaylock RC, et al. Intravenous catheter
aspiration for obtaining basic analytes during intravenous infusion. Ann
Emerg Med. 1990;19: 789-792.
11. Fincher RK, Strong JS, Jackson JL. Accuracy of measurements
of hemoglobin and potassium in blood samples from peripheral catheters. Am
J Crit Care. 1998;7: 439-443.
12. Raisky F, Gauthier C, Marchal A, et al. Haemolyzed samples:
responsibility of short catheters. Ann Biol Chem. 1994;52: 523-527.
13. Sharp MK, Mohammad SF. Scaling of hemolysis in needles
and catheters. Ann Biomed Eng. 1998;26: 788-797.
14. Burns ER, Yoshikawa N. Hemolysis in serum samples drawn
by emergency department personnel versus laboratory phlebotomists. Laboratory
Medicine. 2002;33: 378-380.
Frederick L. Kiechle, MD, PhD
Chairman, Department of Clinical Pathology
William Beaumont Hospital
Royal Oak, Mich.
Member, CAP Publications Committee
Q. How can an albumin/creatinine
ratio on a random specimen (urine) be reported in units of number of grams
creatinine when urinary total protein and creatinine are generally mg/dL?
A. Units for albumin and creatinine are converted to mg/L
and g/L, respectively. The value for albumin is divided by the value for
creatinine, resulting in milligrams of albumin divided by grams of creatinine.
Martin H. Kroll, MD
Pathology and Laboratory Medicine Service
VA Medical Center
Member, CAP Chemistry