Specimen re-draws

Medical Laboratory Observer, June, 2004 by Daniel M. Baer

We are trying to find a benchmark for the re-draw rate of laboratory specimens drawn by nursing personnel in a decentralized phlebotomy setting and submitted to laboratory for testing. The reason we reject specimens and request a re-collection would be for things such as hemolysis, dilution with IV fluid, and QNS. We have set our recollection threshold at <1.4%. Do you have any data that would tell us if that is a sensible target?

This question has been the subject of several Q-Probes exercises by CAP, (1,2,3) and is included in its Q-Track program. (4) In 1995, a report of a study of CBC specimen acceptability involving 703 laboratories showed an average rejection rate of 0.45%. (1) A 1997 report studying 453 laboratories reported that rejection rates at the 10th, 50th (median), and 90th percentile of the labs were 1.35%, 0.31%, and 0.06%, respectively. (2) The most recent Q-Probes study was published in 2002. It reported a study from 202 laboratories. Although this paper is mostly concerned with problems of unsuccessful phlebotomy and the reasons for specimen rejection, it also does report a specimen rejection rate of 0.25%. (3)

The CAP Q-Track study published in 2002 reported on an ongoing program involving about 200 laboratories. It showed that over a two-year period, during which the rejection rate was repeatedly sampled, the rejection rate declined from an average of 0.83% to an average of 0.62%. The best performers had rates about 0.30% rejections. (4)

These studies are not completely comparable because the reasons for rejection are related to the tests for which the blood was collected. The major reason for rejection of hematology specimens was clotted blood, while the main chemistry rejection cause was hemolysis. Other important factors influencing the rejection rates were the occupation and training of the people performing phlebotomy and the setting--inpatient, outpatient, or physician's office.

In judging how your rejection rate stacks up against other labs, it is important to look at the spread of rates over the statistical distribution of the labs and to compare your setting and level of personnel with others in the studies. I recommend reading these four papers because they give much more insight into the causes of poor specimens and suggest measures that can be taken to improve the quality of your collections.

References

1. Jones BA, Meier F, Howanitz PJ. Complete blood count specimen acceptability; a College of American Pathologists Q-Probes study of 703 laboratories. Arch Pathol Lab Med. 1995. March;119(3):203-208.

2. Jones BA, Calam RR, Howanitz PJ. Chemistry specimen acceptability: a College of American Pathologists Q-Probes study of 453 laboratories. Arch Pathol Lab Med. 1997. January;121(1):19-26.

3. Dale JC, Novis DA. Outpatient phlebotomy success and reasons for specimen rejection: a Q-Probes study. Arch Pathol Lab Med. 2002. April;126(4):416-419.

4. Zarbo RJ, Jones BA, Friedberg RC, Valenstein PN, Renner SW, Schifman RB, et al. Q-Tracks; A College of American Pathologists Program of Continuous Laboratory Monitoring and Longitudinal Performance Tracking Archives of Pathology and Laboratory Medicine. 2002. September;126(9):1036-1044.

--Daniel M. Baer, MD

Professor Emeritus

Department of Pathology

Oregon Health and Science University

Portland, OR

Daniel M. Baer is professor emeritus of laboratory medicine at Oregon Health and Science University in Portland. OR, and a member of MLO's editorial advisory board.