Evaluation: Difference between revisions

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File:Histopathology of intravascular neutrophils.jpg|However, disregard intravascular white blood cells.

</gallery>

==Counts per mm2==

There are multiple situations where a finding will be quantified in terms of amount per mm2. To make such calculations, you need to know the size of the area you see in the microscope. It is usually possible to look up what theoretically would be the area, but the most reliable way of knowing is to use a calibration slide (basically a translucent ruler with 0.1 mm line resolution or smaller) to measure the diameter of your view. The area is then calculated as:

<math>Area = π\frac{diameter}{4}</math>

Sometimes "high power field" (HPF) is used for area, but it has a substantially different area for different microscopes, for example:

{|class="wikitable"

! Microscope type !! Area per HPF

|-

|

*Olympus BX50, BX40 or BH2 or AO or Nikon with 15x eyepiece

*Olympus BX43 with 10x eyepiece

| 0.096 mm2 <ref name=stanford>{{cite web|url=http://surgpathcriteria.stanford.edu/breast/infductcabr/grading.html|title=Infiltrating Ductal Carcinoma of the Breast (Carcinoma of No Special Type)|website=Stanford University School of Medicine|accessdate=2019-10-02}}</ref>

|-

| AO with 10x eyepiece || 0.12 mm2 <ref name=stanford/>

|-

| Nikon Eclipse E400 with 10x eyepiece and 40x objective || 0.25 mm2

|-

| Leitz Ortholux || 0.27 mm2 <ref name=stanford/>

|-

| Leitz Diaplan || 0.31 mm2 <ref name=stanford/>

|}

For practical purposes, such as when your instructions are to count a specific number of HPFs, one HPF can be assumed to be 0.2 mm2.<ref name="KlimstraModlin2010">{{cite journal|last1=Klimstra|first1=David S.|last2=Modlin|first2=Irvin R.|last3=Coppola|first3=Domenico|last4=Lloyd|first4=Ricardo V.|last5=Suster|first5=Saul|title=The Pathologic Classification of Neuroendocrine Tumors|journal=Pancreas|volume=39|issue=6|year=2010|pages=707–712|issn=0885-3177|doi=10.1097/MPA.0b013e3181ec124e}}</ref> If the view in your microscope significantly differs from this area, calculate how many locations you need to count as:

<math>Locations = HPFs required x \frac{0.2}{Your microscope area}</math>

For example, if you should count 10 HPFs and each view in your microscope shows 0.096 mm2, you should count in this many locations:

<math>10 x \frac{0.2}{0.096} \approx 21</math>

@@ Line 43: / Line 43: @@
 File:Histopathology of intravascular neutrophils.jpg|However, disregard intravascular white blood cells.
 </gallery>
+==Counts per mm<sup>2</sup>==
+There are multiple situations where a finding will be quantified in terms of amount per mm<sup>2</sup>. To make such calculations, you need to know the size of the area you see in the microscope. It is usually possible to look up what theoretically would be the area, but the most reliable way of knowing is to use a calibration slide (basically a translucent ruler with 0.1 mm line resolution or smaller) to measure the diameter of your view. The area is then calculated as:
+<math>Area = π\frac{diameter}{4}</math>
+Sometimes "high power field" (HPF) is used for area, but it has a substantially different area for different microscopes, for example:
+{|class="wikitable"
+! Microscope type !! Area per HPF
+|-
+|
+*Olympus BX50, BX40 or BH2 or AO or Nikon with 15x eyepiece
+*Olympus BX43 with 10x eyepiece
+| 0.096 mm<sup>2</sup> <ref name=stanford>{{cite web|url=http://surgpathcriteria.stanford.edu/breast/infductcabr/grading.html|title=Infiltrating Ductal Carcinoma of the Breast (Carcinoma of No Special Type)|website=Stanford University School of Medicine|accessdate=2019-10-02}}</ref>
+|-
+| AO with 10x eyepiece || 0.12 mm<sup>2</sup> <ref name=stanford/>
+|-
+| Nikon Eclipse E400 with 10x eyepiece and 40x objective || 0.25 mm<sup>2</sup>
+|-
+| Leitz Ortholux || 0.27 mm<sup>2</sup> <ref name=stanford/>
+|-
+| Leitz Diaplan || 0.31 mm<sup>2</sup> <ref name=stanford/>
+|}
+For practical purposes, such as when your instructions are to count a specific number of HPFs, one HPF can be assumed to be 0.2 mm<sup>2</sup>.<ref name="KlimstraModlin2010">{{cite journal|last1=Klimstra|first1=David S.|last2=Modlin|first2=Irvin R.|last3=Coppola|first3=Domenico|last4=Lloyd|first4=Ricardo V.|last5=Suster|first5=Saul|title=The Pathologic Classification of Neuroendocrine Tumors|journal=Pancreas|volume=39|issue=6|year=2010|pages=707–712|issn=0885-3177|doi=10.1097/MPA.0b013e3181ec124e}}</ref> If the view in your microscope significantly differs from this area, calculate how many locations you need to count as:
+<math>Locations = HPFs required x \frac{0.2}{Your microscope area}</math>
+For example, if you should count 10 HPFs and each view in your microscope shows 0.096 mm<sup>2</sup>, you should count in this many locations:
+<math>10 x \frac{0.2}{0.096} \approx 21</math>
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Evaluation: Difference between revisions

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