Metric Calibration Tutorial

Overview

Module 1. Introduction

This section explains basic concepts of Calibration and helps you understand how to assess Metric’s Calibration report and related statistics. Calibration enables accurate IHC test results across different labs. Calibration is mandatory for all types of clinical lab testing except for IHC testing. Calibration is a method that measures the sensitivity of an assay in...

Module 2. What are IHCalibrators®?

Physical Characteristics BCS IHCalibrators, which enable IHC Calibration, are described below. (Figure 1) 15 small round spots pre-printed on a microscope slide. The spots are glass microbeads covalently coated with a biomarker. Each bead has a defined concentration of biomarker traceable to a primary NIST standard. The numbers provide an orientation to the sequence of...

Module 3. Metric Calibration Workflow Steps

BCS’ Calibration Workflow fits seamlessly into your lab’s existing IHC Workflow. Calibration Workflow Step 1: Stain Your IHC lab should stain the IHCalibrators slide using the identical processes used for staining patient tissue samples. Calibration Workflow Step 2: Scan Once the IHCalibrators slide has been stained following the identical processes used within your IHC lab...

Module 4. Understanding Metric Calibration Report

Once you have uploaded Calibrator slide images to Metric, the IHCalculations software automatically: Analyzes the images and quantifies the stain intensity of the images. Produces a Metric Calibration Report. Figure 4 below provides an example of a Metric Calibration Report. We have provided annotations (Text box and A, B, and C below) to explain the...

Module 5. Selecting an IHControl for Statistical Process Control (SPC)

Selecting an IHControl for SPC The Metric Calibration Report calculates and illustrates key parameters of your assay. These key parameters are defined below in Table 1 and shown below in Figure 5. Assay Parameters Terms Definition What is the significance? Analytic Response Curve A in Figure 5 Graphical representation of the relationship of stain intensity...

Module 6. Understanding Lower Limit Of Detection (LOD)

Metric calculates LOD, which quantifies the analytic sensitivity of your assay. LOD is the single most important output of the Metric Calibration Report. Connecting LOD and Assay Analytic Sensitivity Figure 7 below shows the connections between LOD and assay analytic sensitivity, tissue stain intensity, and IHC test errors. LOD quantifies assay analytic sensitivity, which in...

Module 7. Compare LOD With Peer Labs

The LOD calculation provided in the Metric Calibration Report provides quantification of your assay’s analytic sensitivity. You can compare your assay’s LOD with those of peer labs from sources outlined below Figure 6. Analytic sensitivity, as measured by the lower limit detection (y axis), for the various commercial assays by participating laboratories (x axis). Each...

Module 8. Why Does LOD Affect Tissue Staining?

Why does LOD affect tissue staining? The simple waterline model shown in Figure 10 below shows how assay analytic sensitivity determines whether a biomarker remains hidden, faintly visible, or fully revealed. The analytic sensitivity is like the water level. The underwater volcano is like the biomarker. An insensitive assay (A, on left) has a high...

Module 9. Avoid Strong Positive Tissue Controls

A final point about Calibration is to explain why it is important to avoid selecting strongly positive tissue controls (Figure 11). Strongly positive samples are terrible controls, very insensitive. Strongly positive tissue controls can be misleading. If an assay is beginning to show drift, a control in the plateau range often will not show the...

Module 10. Summary: Understanding Metric Calibration

Calibration is designed to improve consistency and comparability of IHC results across laboratories or across instruments within a laboratory. The Metric Calibration Workflow steps include: Stain; Scan, Analyze, and Assess. The Metric Calibration Report calculates and illustrates key parameters of your assay, including LOD. LOD quantifies assay analytic sensitivity, which affects tissue stain intensity. Tissue...