Q&A column, 9/17

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1. Smock KJ, Perkins SL. Examination of the blood and bone marrow. In: Greer JP, Arber DA, Glader B, et al., eds. Wintrobe’s Clinical Hematology. 13th ed. Philadelphia, Pa.: Wolters Kluwer Health; 2014.
2. Cell-Dyn Ruby [operator’s manual]. Abbott Park, Ill.: Abbott Laboratories; 2006.

Etienne Mahe, MD, MSc, Pathologist, Division of Hematology Department of Pathology and Laboratory Medicine, University of Calgary, Alberta, Canada
Member, Hematology/Clinical Microscopy Resource Committee

Q. How is the heparin therapeutic range established and verified? How many patient samples are needed to establish the range?

A. The anti-factor Xa assay is designed to measure plasma heparin (unfractionated heparin [UH] and low-molecular-weight heparin [LMWH]) levels and to monitor anti­coagulant therapy.

Therapeutic ranges of heparin are as follows: LMWH: 0.5–1.2 IU/mL; UH: 0.3–0.7 IU/mL. Prophylactic ranges of heparin are as follows: LMWH: 0.2–0.5 IU/mL; UH: 0.1–0.4 IU/mL.
If APTT is used to measure UH, an anti-Xa assay should be used as a reference method, and citrated plasma samples from a minimum of 40 patients should be used to establish ranges of APTT.

Olson JD. How to validate heparin sensitivity of the aPTT. CAP TODAY. 2004;18(10):72–78.

Dong Chen, MD, PhD, Pathologist Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minn.
Chair, Coagulation Resource Committee

Q. Is there a regulation that addresses the submission of proficiency testing results with regard to faxing and electronic reporting and the location of testing and reporting?

A. Laboratories have different options for submitting proficiency testing results, such as faxing or electronic submission. They need to follow instructions from the PT provider on how to submit the results. CAP checklist requirements COM.01800 and COM.01900 and CLIA regulation 42 CFR 493.801(b) address the potential problems relating to proficiency testing interlaboratory communication and referral of testing. Laboratories must ensure that the testing is performed at the location of the laboratory for which the proficiency testing was ordered and that the results are reported from that same laboratory location (i.e. same CLIA number/CAP number). The laboratory cannot send the samples or the results to another laboratory prior to the deadline for submission of the results to the PT provider.

Lyn Wielgos, MT(ASCP), Checklist Editor, CAP Accreditation Programs
College of American Pathologists Northfield, Ill.
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Dr. Kiechle is a consultant, clinical pathology, Cooper City, Fla. Use the reader service card to submit your inquiries, or address them to Sherrie Rice, CAP TODAY, 325 Wau­ke­gan Road, Northfield, IL 60093; srice@cap.org. Those questions that are of general interest will be answered.