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Point of Care Testing Compared to Laboratory Testing for the Assessment of White Blood Cell Counts and Differentials: A Review of the Clinical Effectiveness, Diagnostic Precision and Accuracy, Cost-Effectiveness, and Guidelines

Published on: October 15, 2013
Project Number: RC0489-000
Product Line: Rapid Response
Research Type: Devices and Systems
Report Type: Summary with Critical Appraisal
Result type: Report

Report in Brief

Context
White blood cell counts and differential counts, or “differentials,” are tests that are typically used to diagnose and monitor a variety of conditions such as bacterial or viral infections, inflammation, leukemia, or immune system deficiency (which is a common side effect of chemotherapy). A white blood cell count measures the concentration of white blood cells, while a differential measures the percentage of each of the five types of white blood cells. Both are frequently part of a complete blood cell count workup during a routine health checkup.

Technology
After drawing a blood sample from a patient, white blood cell counts and differentials are performed in central laboratories using blood analyzers. Point-of-care (POC) testing technologies are currently being developed with the aim of reducing the turnaround time for receiving blood cell count results and, therefore, allowing for more timely medical decisions to be made in remote sites or in outpatient settings.

Issue
A review of the clinical effectiveness, accuracy, precision, and cost-effectiveness of POC testing technologies compared with central laboratory methods to assess patients’ white blood cell counts and differentials, as well as a review of the guidelines on the use of POC testing for these purposes, will help inform decisions about which testing method to use for these patients.

Methods
A limited literature search was conducted of key resources, and titles and abstracts of the retrieved publications were reviewed. Full-text publications were evaluated for final article selection according to predetermined selection criteria (population, intervention, comparator, outcomes, and study designs).

Results
The literature search identified 409 citations, with 4 additional articles identified from other sources. Of these, 21 were deemed potentially relevant and 5 met the criteria for inclusion in this review — 4 observational studies and 1 guideline.

Key Messages

  • In general, POC testing technologies are as accurate and precise as analyzers in centralized laboratories.
  • No studies comparing the clinical or cost-effectiveness of POC testing with that of standard laboratory testing were found.

Question

  1. What is the clinical effectiveness of the point of care testing (POCT) technologies to assess white blood cell counts (WBC) and differentials when compared to clinical laboratory test methods?
  2. What is the diagnostic accuracy and precision of the POCT technologies to assess WBC counts and differentials when compared to clinical laboratory testing methods?
  3. What is the cost-effectiveness of using PCOT to assess WBC counts and differentials when compared to clinical laboratory testing methods?
  4. What are the guidelines associated with the use of POCT to asses WBC counts and differentials?

Key Message

In general, POC testing is reliable and produces comparable results to a standard reference analyzer. The HemoCue WBC analyzer was also found to be stable under different conditions, and the counts can be interfered by a number of pathologic conditions. A guideline from the International Council for Standardization in Hematology (ICSH) was developed in 2008 to provide information on how to develop and manage a POC service so that reliable hematology results are produced. There were no studies on comparative clinical effectiveness, and cost effectiveness between POC WBC testing and standard laboratory testing.

Tags

leukocyte count, leukocytes, point-of-care systems, point of care, Hemocue WBC, point-of-care, POC, POCT, Sysmex pocH-100i, WBC, hemoglobinometers, hemoglobinometer, Portable, Ambulatory, portaWBC