Hematology: neutrophil

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Sections available in full article Overview, Uses, Sampling, Source of test material, Quantity of test material, Sample collection technique, Result data, Normal (reference) values, Abnormal values, Sources, Publications, Vetstream contributor(s),
Contributors Dr Kathleen P Freeman DVM MS PhD MRCVS
Dr Karen L Gerber BVSc(Hons) DipACVP(clin path) MRCVS Accredited Specialist Clinical Pathologist (Australia)
Dr Andy Torrance MA VetMB PhD DipACVIM MRCVS

Overview

  • Neutrophils phagocytose and digest foreign material in acute infectious or non-infectious inflammation.
  • The degree of [neutrophil] increase (neutrophilia) and presence or absence of left-shift provides a valuable diagnostic (in combination with other tests) and prognostic tool in many diseases.
  • Left-shift .
  • Degenerative left-shift (left-shift without increased neutrophils): excessive neutrophil consumption.
  • Marked left-shift (bands and metamyelocytes)  Hematology: band neutrophil    →   acute to peracute, suppurative diseases. Any stage younger than the metamyelocyte is not capable of phagocytosis.
  • Neutrophils are short-lived (approximately 4 days).

Uses

In combination

  • Part of the leucogram  Hematology: leucogram  .

Non-specific diseases

  • Infections - in combination with leucogram.
  • Septicemia and overwhelming bacterial infections - may have leucopenia with degenerative left-shift.
  • Corticosteroids - in combination with leucogram (eosinopenia, lymphopenia and monocytosis) and biochemistry.
  • Inflammation - usually with left-shift (acute).
  • Leukemias and lymphoproliferative disorders  Lymphoproliferative disease  (recognition of abnormal lymphocytes and lymphoblasts or immature and atypical myeloid cells).

Anemia

  • Hemolytic or hemorrhagic anemia - neutrophilia often seen with left-shift.
  • Infection/inflammation in some body areas, eg enteritis, dermatitis, tracheobronchitis, but can also have inflammation in organ/system open to outside, eg urinary/gastrointestinal tract without neutrophilia.

Other points

Neutrophil kinetics
  • Proliferating pool: myeloblast, progranulocyte (promyelocyte), and myelocyte.
  • Maturation pool: metamyelocyte, band neutrophil  Hematology: band neutrophil  and segmented granulocyte.
  • Marginal neutrophilic pool (MNP) - one neutrophil for each neutrophil circulating in small blood vessels.
  • Circulating neutrophilic pool (CNP) - in larger blood vessels. Half-life approximately 6-7 hours, ie entire population replaced 2.5 times daily.
  • Tissue migration within 2 hours of injury. Neutrophils do not return to circulation, but either enter body cavities (gut, pulmonary secretions, urine, saliva) or are phagocytosed.
  • In dogs, the circulating and marginal pools are about equal. A cat has a marginal pool two to three times its circulating pool.

Result data

Normal (reference) values

  • May vary with age, sex.
  • 2.5-12.5 x 10*9/l.

Abnormal values

  • Acute infection, especially with pyogenic bacteria, usually results in the appearance of band forms (left-shift), and sometimes earlier forms in very severe cases. Chronic infections have mature neutrophils with smaller or absent left shift and often monocytosis.
    Neutrophilia
  • Infection (especially pyogenic bacteria).
  • Tissue inflammation/necrosis.
  • Hyperadrenocorticism or corticosteroid treatment.
  • Stress (endogenous corticosteroid release) - total leucocyte count usually <3 x 10*9/l.
  • Leucoerythroblastic responses.
  • Auto-immune hemolytic anemia  Anemia: immune-mediated hemolytic  .
  • Drug toxicity - estrogen (acute).
  • Neoplasia.
  • Leukemia  Leukemia  .
  • Neutrophilia may also be due other to non-inflammatory disorders, eg intoxication, anesthetics and occasionally metabolic disorders.
    Neutropenia
  • Excessive destruction or utilization, sequestration, reduced granulopoiesis, impaired movement out of bone marrow and congenital defects.
  • Overwhelming acute or chronic bacterial infection, especially if involve large surface area, eg peritonitis  Peritonitis  .
  • Viral infection (acute), eg feline parvovirus  Feline panleucopenia virus disease  , feline leukemia virus (FeLV)  Feline leukemia virus disease  , feline immunodeficiency virus (FIV)  Feline immunodeficiency virus disease  or infection with gram-negative neutrophils.
  • Hypersplenism.
  • Shock - endotoxic, septic, anaphylactic (pseudoneutropenia).
  • Drugs.
  • Estrogen-producing testicular tumors, ie Sertoli cell tumors.
  • Toxemia, eg uremia  Uremia  .
  • Neoplasia.
  • Myelokathexis (neutropenia resulting from bone marrow retention in the face of adequate reserves).

Sources

Publications

Refereed papers

  • Brown M R & Rogers K S (2001) Neutropenia in dogs and cats - a retrospective study of 261 cases. JAAHA 37, 131-139.
  • Lucroy M D& Madewell B (2001) Clinical outcome and diseases associated with extreme neutrophilic leukocytosis in cats - 104 cases (1991-1999). JAVMA 218, 736-739.

Other sources of information

  • Cowell R L, Tyler R D & Meinkoth J H (1999) Diagnostic Cytology and Hematology of the Dog and Cat. 2nd edn. St Louis: Mosby.
  • Duncan J R, Prasse K W & Mahaffy E A (1994) Veterinary Laboratory Medicine Clinical Pathology. 3rd edn. Ames: Iowa University Press.
  • Jain N C (1993) Essentials of Veterinary Hematology. Philadelphia: Lea & Febiger.

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