Leukogram Patterns
Stress (cortisol-mediated) leukogram
Expected CBC findings:
• ± Mild neutrophilia (neutrophilia < 2x URL)
• No left shift
• Lymphopenia* (best support)
Chemistry findings (may or may not be present):
• Hyperglycemia (due to cortisol)
•
± Monocytosis
± Eosinopenia
•
•
Increased ALP activity (cortisol effects, dogs only)
Excitement or physiologic (epinephrine-mediated) leukogram
Expected CBC findings:
• Mild neutrophilia (neutrophilia < 2x URL)*
• Erythrocytosis (splenic contraction)
• No left shift
• Thromobocytosis (splenic contraction)
• Mild lymphocytosis
Chemistry findings (may or may not be present):
• Hyperglycemia (related to epinephrine effects, multifactorial)
Inflammatory leukogram
Expected CBC findings to support an interpretation of an inflammatory leukogram:
• Neutrophil count >2x URL
• Concurrent left shift
• Neutrophil toxic change (cytoplasmic basophilia, cytoplasmic foamy vacuolization, Dohle bodies, retained
primary granules, donut-shaped nuclei)
• Neutrophilia < 2x URL (without another obvious cause, i.e. stress or inflammation) – must be proven
• Overwhelming inflammation causing neutropenia or a degenerative left shift
• Lymphocytosis suggesting chronic inflammation – look for concurrent neutrophilia and/or left shift and/or
neutrophil toxic change and/or monocytosis; See document on lymphocytosis for further information
• Monocytosis (especially if > 2x URL)
• Eosinophilia +/- Basophilia
Stress
Segmented neutrophils*
↑
Excitement/
Acute
Chronic
Overwhelming
Physiologic
inflammation
inflammation
inflammation
↑
N-↑-↑↑↑
↑-↑↑↑↑
↓-N
±↑
±↑
±↑
±
±
±
±↓ (if stress)
±↑
±↓ (if stress)
Band neuts. or earlier
Neutrophil toxic change
Lymphocytes
↓
Monocytes
±↑
±↑ (if stress)
±↑
±↑ (if stress)
Eosinophils
±↓
±↓ (if stress)
±↑
±↓ (if stress)
↑
*Magnitude of neutrophilia (segmented): ↑, Mild (< 2 x URL); ↑↑, Moderate (2-3 x URL); ↑↑↑, Marked (≥ 4 x URL)
PVMA - November 2016 - Nicole Weinstein, DVM, DACVP – Penn Vet Clinical Pathology
Specific terminology or cutoffs
•
•
Acutevs.chronicinflammation–Thereisapproximatelya5-daysupplyofneutrophilsinthe
storagepool.Themarrowisfirstdepletedofsegmentedneutrophils,thenbands,then
metamyelocytes,andsoon.Neutrophilsarereleasedfromthematurationpoolintotheblood
resultinginneutrophilia±leftshiftthatlastsabout2-5days.Depletionofstoragepoolneutrophils
duringtheacutephasestimulatesgranulopoiesis,whichreplenishesthestoragepool.The
leukogrammayrevealaneutrophiliawithorwithoutaleftshift,dependingonthedegreeoftissue
inflammation.Productiontendstoequaldemand,andtheincreasedreleaseofneutrophilsfrom
themarrowmayexceedthemigrationofneutrophilsintotheinflamedtissues.Thistakesovera
weektoreachthischronicphase.Attimes,theneutrophiliamaypersistpasttheresolutionof
inflammationuntilbonemarrowgranulopoiesisnormalizes.Oncegranulocytichyperplasiastarts,it
mustcontinueuntilallofthesurplusneutrophilsarereleasedintoblood.Therefore,theWBCcount
maycontinuetoincreaseornotdecrease,evenafterthesourceofinflammationhasbeen
removed.Therewilloftenbeaconcurrentmonocytosiswithchronicinflammationasthe
stimulatingfactoraffectsbothneutrophilandmonocytedevelopment.
Overwhelminginflammation–identifiedbythepresenceofa‘degenerativeleftshift,’where
immatureneutrophilsexceedmatureneutrophilsintheperipheryorthereisaneutropenia+aleft
shift.Thistypicallyreflectsanacuteinflammatoryprocess,wherematureneutrophilsutilization
exceedstheabilityofthemarrowto‘keepup.’Othercausesofneutropeniashouldbeexcluded,i.e.
decreasedproductionofneutrophilsbythebonemarrow,immune-mediatedneutrophil
destruction(rare),EDTA-inducedartifactualneutrophilclumping(incats),or,ifonlyamild
decrease,duetonormalvariation,e.g.averycalmanimal.
•
Leukemoidresponse–neutrophilnumbers(any/alltypes)>50,000/uL
o Subtypeofchronicinflammation
o Calledleukemoid(leukemia-like)givennumbersofWBCsareincreasedsimilartoleukemia
o Causes:
§ Immune-mediatedhemolyticanemia(IMHA)withresultingtissuenecrosis/death
fromsevereanemia-inducedhypoxemia(e.g.centrilobularhepaticnecrosis)and/or
thromboembolicdisease
§ The‘Ps’–Pyometra(&stumppyometra),pyothorax,peritonitis,pyelonephritis
(lookforazotemia),pneumonia(chronic,notacutepneumonia),paraneoplastic
(rare)
§ Neoplasiawithtumornecrosisorsevereassociatedtissueinflammation
§ Hepatozoonamericanuminfection(southernUSA,Texas)
§ Granulocyticorneutrophilicleukemia(atypeofchronicmyeloproliferativedisease)
istheneoplasticdifferential–rare;othercausesmustberuledout
Neoplastic leukogram
Possible causes:
• Acute leukemia – acute lymphoid leukemia; acute myeloid (i.e. non-lymphoid cells) with a variety of
subclassifications, i.e. erythroid leukemia (cats); acute undifferentiated leukemia; etc.
• Chronic leukemia – Chronic lymphocytic leukemia; Chronic myeloproliferative disease aka chronic myeloid
leukemia (rare), e.g. polycythemia vera, essential thrombasthenia, chronic eosinophilic leukemia, etc
• Circulating neoplastic cells – Secondary to circulating neoplastic lymphoid cells with lymphoma
PVMA - November 2016 - Nicole Weinstein, DVM, DACVP – Penn Vet Clinical Pathology