Peripheral blood smear: Difference between revisions

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==Red blood cells==
==Red blood cells==
{|class=wikitable align=right
===Automated values===
! RDW in adults<ref name=MrLabTest>{{cite web|url=https://www.mrlabtest.com/high-RDW-blood.htm|website=MrLabTest|title=High RDW level in the blood}} Last update: 12/01/2021</ref> !! Terminology<ref name=MrLabTest/>
When available, automatic quantification of mean corpuscular volume (MCV) and red blood cell (RBC) distribution width (RDW), usually as part of CBC panel, generally decides whether you will call the sample "'''normocytic'''" versus "microcytic"/"macrocytic" and/or "anisocytotic", even if it is not clearly visible in the microscope. If automated values are not available, compare RBC sizes to lymphocyte nuclei, which should normally be the same size. If mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC) are normal, but you still see multiple RBCs with central pallor greater than 50% of the diameter, you can report it as ''"Increased central pallor"'', and you may add ''"indicating iron deficiency"'' if it is compatible with the clinical history.
|-
| 14.5% - 18% || Mild anisocytosis
|-
| 18% - 26% || Moderate anisocytosis
|-
| > 26% || Severe anisocytosis
|}


Peripheral blood findings are grades as follows:<ref>{{cite web|url=http://www.hkimls.org/qapeduhsm-rbc-mor.htm|title=Hong Kong Medical Technology Association - Quality Assurance Programme - Haematology and Serology, Prepared by HKMTAQAP Haematology & Serology Panel on November 2002.}}</ref>
Automated values can be graded as follows:<ref name=HongKong>Unless otherwise specified in table, reference is:<br>- {{cite web|url=http://www.hkimls.org/qapeduhsm-rbc-mor.htm|title=Hong Kong Medical Technology Association - Quality Assurance Programme - Haematology and Serology, Prepared by HKMTAQAP Haematology & Serology Panel on November 2002.}}</ref>
{|class=wikitable
{|class=wikitable
! Grade
! +
! ++
! +++
|-
|-
! Interpretation
! Interpretation
! Mild/rare/occasional
! Mild
! Moderate
! Moderate
! Marked/Numerous
! Marked
|-
|-
|  Microcytosis||MCV : 70 - 79||MCV : 60 - 69||MCV <60
|  Microcytosis ||MCV : 70 - 79||MCV : 60 - 69||MCV <60
|-
|-
|  Macrocytosis||MCV : 100 - 115||MCV : 115 - 125||MCV >125
|  Macrocytosis ||MCV : 100 - 115||MCV : 115 - 125||MCV >125
|-
|-
|  Hypochromasia||MCH : 23 - 26||MCH : 21 - 23||MCH <20
|  Hypochromasia||MCH : 23 - 26||MCH : 21 - 23||MCH <20
|-
|-
|  Anisocytosis||RDW: 16-18||RDW : 18-22||RDW>22
|  Anisocytosis||RDW: 14.5<ref name=MrLabTest>{{cite web|url=https://www.mrlabtest.com/high-RDW-blood.htm|website=MrLabTest|title=High RDW level in the blood}} Last update: 12/01/2021</ref> !! Terminology<ref name=MrLabTest/>  or 16<ref name=HongKong/> - 18||RDW : 18 - 22<ref name=HongKong/> or 26<ref name=MrLabTest/> ||RDW > 22<ref name=HongKong/> or 26<ref name=MrLabTest/>
|-
|-
| Polychromasia||3 - 5%||5 - 25%||>25%
|}
 
===Morphologic findings===
Look for poikilocytosis (red blood cells of abnormal shapes):
[[File:Micrograph of an echinocyte on a peripheral blood smear.jpg|thumb|210px|'''Echinocytes''' ("burr cells"), are distinguished from acanthocytes by having more equally distributed and rounded projections. They are usually [[Artifacts|artifactual]], not needing reporting. However, they may also be caused by renal insufficiency, so if this is present, a report may include "Occasional/Multiple echinocytes, consistent with renal insufficiency".]]
<gallery mode=packed heights=150>
File:Human blood film with acanthocytes 02.jpg|'''Acanthocytes''' ("spur cells")
File:Micrograph of an elliptocyte on a peripheral blood smear 02.jpg|thumb|'''Elliptocytes'''
</gallery>
These are counted as a percentage of visible red blood cells:<ref name=HongKong/>
{|class=wikitable
|-
|-
| Spherocytes||1 - 5%||5 - 25%||>25%
! Interpretation
! Rare/Occasional
! Moderate amount of
! Many/Abundant
|-
| Polychromasia||3 - 5%||5 - 25%||>25%
|-
| Spherocytes||1 - 5%||5 - 25%||>25%
|-
|-
| Schistocytes||up to 2%||2 - 25%||>25%
| Schistocytes||up to 2%||2 - 25%||>25%
|-
|-
| Target cells (codocytes)||up to 3%||3 - 25%||>25%
| Target cells (codocytes)||up to 3%||3 - 25%||>25%
|-
|-
| Tear drop cells||up to 2%||2 - 25%||>25%
| Tear drop cells||up to 2%||2 - 25%||>25%
|-
|-
| Burr cells (echinocytes)||1 - 3%||3 - 10%||>10%
| Burr cells (echinocytes)||1 - 3%||3 - 10%||>10%
|-
|-
| Sickle cells (drepanocytes)||3 - 5%||5 - 25%||>25%
| Sickle cells (drepanocytes)||3 - 5%||5 - 25%||>25%
|-
|-
| Elliptocytes||1 - 5%||5 - 25%||>25%
| Elliptocytes||1 - 5%||5 - 25%||>25%
|-
|-
| Basophilic stipplings||up to 2%||2 - 25%||>25%
| Basophilic stipplings||up to 2%||2 - 25%||>25%
|-
|-
| Howell Jolly bodies||up to 1%||2 - 3 %||>3%
| Howell Jolly bodies||up to 1%||2 - 3 %||>3%
|-
|-
|}
|}
When available, automatic quantification of mean corpuscular volume (MCV) and red blood cell (RBC) distribution width (RDW), usually as part of CBC panel, generally decides whether you will call the sample "'''normocytic'''" versus "microcytic"/"macrocytic" and/or "anisocytotic", even if it is not clearly visible in the microscope. If automated values are not available, compare RBC sizes to lymphocyte nuclei, which should normally be the same size. If mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC) are normal, but you still see multiple RBCs with central pallor greater than 50% of the diameter, you can report it as ''"Increased central pallor"'', and you may add ''"indicating iron deficiency"'' if it is compatible with the clinical history.
Look for poikilocytosis (red blood cells of abnormal shapes):
[[File:Micrograph of an echinocyte on a peripheral blood smear.jpg|thumb|210px|'''Echinocytes''' ("burr cells"), are distinguished from acanthocytes by having more equally distributed and rounded projections. They are usually [[Artifacts|artifactual]], not needing reporting. However, they may also be caused by renal insufficiency, so if this is present, a report may include "Occasional/Multiple echinocytes, consistent with renal insufficiency".]]
<gallery mode=packed heights=150>
File:Human blood film with acanthocytes 02.jpg|'''Acanthocytes''' ("spur cells")
File:Micrograph of an elliptocyte on a peripheral blood smear 02.jpg|thumb|'''Elliptocytes'''
</gallery>
'''Schistocytes''' (fragmented parts red blood cells) only needs mentioning if constituting over 1% of red blood cells or at least 2 per oil immersion field.


<gallery mode=packed heights=150>
<gallery mode=packed heights=150>

Revision as of 20:12, 17 December 2021

Author: Mikael Häggström [note 1]

Look at and comment separately on white blood cells, red blood cells and platelets.

Oil immersion microscopy

This is preferred for light microscopy of peripheral blood smears in order to achieve a very high magnification. First use low or medium power to center on suspicious cells, or where red or white blood cells are best appreciated. Put a drop of immersion oil on the location and switch to the immersion objective. Be systematic in your switching between objectives so as to avoid getting oil on any of your dry objectives (which is a bit tedious to clean off).

Red blood cells

Automated values

When available, automatic quantification of mean corpuscular volume (MCV) and red blood cell (RBC) distribution width (RDW), usually as part of CBC panel, generally decides whether you will call the sample "normocytic" versus "microcytic"/"macrocytic" and/or "anisocytotic", even if it is not clearly visible in the microscope. If automated values are not available, compare RBC sizes to lymphocyte nuclei, which should normally be the same size. If mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC) are normal, but you still see multiple RBCs with central pallor greater than 50% of the diameter, you can report it as "Increased central pallor", and you may add "indicating iron deficiency" if it is compatible with the clinical history.

Automated values can be graded as follows:[1]

Interpretation Mild Moderate Marked
Microcytosis MCV : 70 - 79 MCV : 60 - 69 MCV <60
Macrocytosis MCV : 100 - 115 MCV : 115 - 125 MCV >125
Hypochromasia MCH : 23 - 26 MCH : 21 - 23 MCH <20
Anisocytosis RDW: 14.5[2] !! Terminology[2] or 16[1] - 18 RDW : 18 - 22[1] or 26[2] RDW > 22[1] or 26[2]

Morphologic findings

Look for poikilocytosis (red blood cells of abnormal shapes):

File:Micrograph of an echinocyte on a peripheral blood smear.jpg
Echinocytes ("burr cells"), are distinguished from acanthocytes by having more equally distributed and rounded projections. They are usually artifactual, not needing reporting. However, they may also be caused by renal insufficiency, so if this is present, a report may include "Occasional/Multiple echinocytes, consistent with renal insufficiency".

These are counted as a percentage of visible red blood cells:[1]

Interpretation Rare/Occasional Moderate amount of Many/Abundant
Polychromasia 3 - 5% 5 - 25% >25%
Spherocytes 1 - 5% 5 - 25% >25%
Schistocytes up to 2% 2 - 25% >25%
Target cells (codocytes) up to 3% 3 - 25% >25%
Tear drop cells up to 2% 2 - 25% >25%
Burr cells (echinocytes) 1 - 3% 3 - 10% >10%
Sickle cells (drepanocytes) 3 - 5% 5 - 25% >25%
Elliptocytes 1 - 5% 5 - 25% >25%
Basophilic stipplings up to 2% 2 - 25% >25%
Howell Jolly bodies up to 1% 2 - 3 % >3%

Platelets

If CBC is performed, use count to determine whether platelets are "normal in number" or whether there is "thrombocytopenia" or "thrombocytosis". If no CBC, count platelets within a high power oil immersed field, which should normally be 8 to 20.

In thrombocytopenia from automatic counting, look in particular for:

  • Clumping of platelets (which can cause a falsely low automatic platelet count). If present, check with the lab if it was sent in EDTA (which may cause artefactual clumping) and ask to have a blood sample sent in sodium citrate instead. Also, look for satellitosis (platelets attached around white blood cells).
  • Schistocytes among red blood cells.

The finding of giant platelets may be reported as "Occasional/multiple giants platelets, which suggests increased platelet turnover".

White blood cells

Look for:

When smudge cells constitute more than 10% of white blood cells, or in patients with CLL, a separate smear with a drop of serum albumin to every four or five drops of blood should be made to stabilize cell membranes.[4] Still evaluate red blood cells and platelets on the non-albumin slide.

Notes

  1. ↑ For a full list of contributors, see article history. Creators of images are attributed at the image description pages, seen by clicking on the images. See Patholines:Authorship for details.

Main page

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 Unless otherwise specified in table, reference is:
    - . Hong Kong Medical Technology Association - Quality Assurance Programme - Haematology and Serology, Prepared by HKMTAQAP Haematology & Serology Panel on November 2002..
  2. ↑ 2.0 2.1 2.2 2.3 . High RDW level in the blood. MrLabTest. Last update: 12/01/2021
  3. ↑ Glassy, Eric (1998). Color atlas of hematology : an illustrated field guide based on proficiency testing . Northfield, Ill: College of American Patholgists. ISBN 978-0-930304-66-9. OCLC 40976106. 
  4. ↑ Error on call to Template:cite web: Parameters url and title must be specifiedFredrick L. Kiechle. . CAP Today. June 2010

Image sources


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