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Knowledge articleCell Line Microarrays: Building Reliable IHC and ISH Controls
Purpose-built positive and negative controls with known, uniform expression.
Every IHC run needs one honest witness — a control that tells you the stain actually worked. Most labs reach for a tissue control, and most tissue controls drift from one block to the next. There's a cleaner option that doesn't get talked about enough: a cell line microarray.
What it is
Picture a single paraffin block holding several FFPE cell-line pellets, each with a known, documented level of marker expression. Section it and you've got your positive and your negative sitting side by side on one slide, behaving the same way every time.
Why cell lines beat mystery tissue
Characterised lines express a marker at a consistent, written-down level — so your "known positive" really is one. You get both a positive and a negative on the same section, and far less of the block-to-block wobble that heterogeneous tissue gives you. For quality control, that predictability is the whole point.
How they're built
The lines are pelleted, fixed and made into cell blocks (the same cell block preparation used in cytology), then cores from several blocks are arrayed into one recipient block. One section, all your controls.
Using it in the run
Set the control section alongside the patient slides so it rides through the identical protocol on your slide staining machine or IHC platform. Right result on the known positive and negative? The run's good. Something odd? You've caught a reagent or protocol problem before it reached a report.
One caveat worth its own line
A control is only as trustworthy as the line behind it. Build them from authenticated, uncontaminated lines — see cell line authentication and contamination.
FAQs
What is a cell line microarray?
A paraffin block containing multiple FFPE cell-line pellets with known marker expression, sectioned to provide defined positive and negative controls for IHC and ISH on a single slide.
Why use cell lines instead of tissue as IHC controls?
Characterised cell lines express markers at a known, uniform level, giving more reproducible positive and negative controls than heterogeneous tissue that varies between blocks.
Prepared and reviewed by the Unimeditrek technical team based on laboratory practice, installation and service experience. This document explains histopathology workflow, laboratory practice and equipment based on the questions we hear from hospitals, medical colleges and diagnostic laboratories — vendor-neutral where it explains the science and practical where it explains equipment.
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