Below are blood reference ranges for various types leucocytes/WBCs. The 97.5 percentile (right limits in intervals in image, showing 95% prediction intervals) is a common limit for defining leukocytosis.

The diagnosis is made after a complete blood count, a routine blood test. The absolute neutrophil count in this test will be below 500, and can reach 0 cells/mm³. Other kinds of blood cells are typically present in normal numbers.

To formally diagnose agranulocytosis, other pathologies with a similar presentation must be excluded, such as aplastic anemia, paroxysmal nocturnal hemoglobinuria, myelodysplasia and leukemias. This requires a bone marrow examination that shows normocellular (normal amounts and types of cells) blood marrow with underdeveloped promyelocytes. These underdeveloped promyelocytes, if fully matured, would have been the missing granulocytes.

In patients that have no symptoms of infection, management consists of close monitoring with serial blood counts, withdrawal of the offending agent (e.g., medication), and general advice on the significance of fever.

Transfusion of granulocytes would have been a solution to the problem. However, granulocytes live only ~10 hours in the circulation (for days in spleen or other tissue), which gives a very short-lasting effect. In addition, there are many complications of such a procedure.

Leukopenia can be identified with a complete blood count.

Below are blood reference ranges for various types leucocytes/WBCs. The 2.5 percentile (right limits in intervals in image, showing 95% prediction intervals) is a common limit for defining leukocytosis.

Leukocytosis is very common in acutely ill patients. It occurs in response to a wide variety of conditions, including viral, bacterial, fungal, or parasitic infection, cancer, hemorrhage, and exposure to certain medications or chemicals including steroids.

For lung diseases such as pneumonia and tuberculosis, WBC count is very important for the diagnosis of the disease, as leukocytosis is usually present.

The mechanism that causes leukocytosis can be of several forms: an increased release of leukocytes from bone marrow storage pools, decreased margination of leukocytes onto vessel walls, decreased extravasation of leukocytes from the vessels into tissues, or an increase in number of precursor cells in the marrow.

Certain medications, including corticosteroids, lithium and beta agonists, may cause leukocytosis.

Certain medications can alter the number and function of white blood cells.

Medications that can cause leukopenia include clozapine, an antipsychotic medication with a rare adverse effect leading to the total absence of all granulocytes (neutrophils, basophils, eosinophils). The antidepressant and smoking addiction treatment drug bupropion HCl (Wellbutrin) can also cause leukopenia with long-term use. Minocycline, a commonly prescribed antibiotic, is another drug known to cause leukopenia. There are also reports of leukopenia caused by divalproex sodium or valproic acid (Depakote), a drug used for epilepsy (seizures), mania (with bipolar disorder) and migraine.

The anticonvulsant drug, lamotrigine, has been associated with a decrease in white blood cell count.

The FDA monograph for metronidazole states that this medication can also cause leukopenia, and the prescriber information suggests a complete blood count, including differential cell count, before and after, in particular, high-dose therapy.

Immunosuppressive drugs, such as sirolimus, mycophenolate mofetil, tacrolimus, ciclosporin, leflunomide and TNF inhibitors, have leukopenia as a known complication. Interferons used to treat multiple sclerosis, such as interferon beta-1a and interferon beta-1b, can also cause leukopenia.

Chemotherapy targets cells that grow rapidly, such as tumors, but can also affect white blood cells, because they are characterized by bone marrow as rapid growing. A common side effect of cancer treatment is neutropenia, the lowering of neutrophils (a specific type of white blood cell).

Decreased white blood cell count may be present in cases of arsenic toxicity.

White blood counts exceeding 100 x 10^9 / L (100,000 / microL) present symptoms of tissue hypoxia and may signal possible neurological and respiratory distress. Continuing research has shown that patients have suffered from hypoxia at leukocyte levels below 100 x 10^9 / L (100,000 / microL), therefore patients with leukemia need regular neurological and respiratory monitoring when leukocyte counts are approaching 100 x 10^9 / L (100,000 / microL) to decrease chances of tissue hypoxia. Biopsy's acquired are examined for damage to microvasculature, which serves as evidence of hypoxia through the identification of leukocyte blockage within the tissue. Due to a biopsy's invasive nature and the risks associated with the procedure, it is only used when deemed necessary.

Measurements for arterial pO2 have shown to be falsely decreased in patients with hyperleuckocytosis because of white blood cells ability to utilize oxygen. Pulse oximetry should be used to more accurately assess pO2 levels of a patient suspected to be suffering from leukocytosis.

Automated blood cell counters may be inaccurate due to fragments of blast cells being labeled on blood smears as platelets. The most accurate form of confirming platelet counts is by using a manual platelet count and review of a peripheral smear.

Serum potassium levels may also be artificially elevated caused by a release from leukemic blasts during in vitro clotting process, therefore serum potassium levels should be monitored by herparinized (the addition of herapin prevents coagulation) plasma samples in order to obtain accurate results of potassium levels.

Disseminated intravascular coagulation may occur in a significant amount of patients with presentation of various degrees of thrombin generation, followed by decreased fibrinogen and increased fibrinolysis.

Spontaneous tumor lysis syndrome is present in approximately 10 percent of patients with leuckostasis, lab tests are used to measure the potential of elevated serum concentrations such as uric acid, potassium, phosphate, and hyocalcemia.

Disseminated intravascular coagulation and spontaneous tumor lysis syndrome have the ability to develop before and after chemotherapy treatment. Patients undergoing this type of therapy need to be closely monitored before and after in addition to undergoing prophylactic measures to prevent possible complications.

Since leukostais/ hyperleukostasis is associated with leukemia, preventative treatments are put into action upon diagnosis.

Patients with hyerleukocystois associated with leukemia are always considered candidates for tumor lysis syndrome prophylaxis in addition to aggressive intravenous hydration with allopurinol or rasburicase to decrease serum uric acid levels.

A normal eosinophil count is considered to be less than 0.65/L. Eosinophil counts are higher in newborns and vary with age, time (lower in the morning and higher at night), exercise, environment, and exposure to allergens. Eosinophilia is never a normal lab finding. Efforts should always be made to discover the underlying cause, though the cause may not always be found.

Neutrophils are the primary white blood cells that respond to a bacterial infection, so the most common cause of neutrophilia is a bacterial infection, especially pyogenic infections.

Neutrophils are also increased in any acute inflammation, so will be raised after a heart attack, other infarct or burns.

Some drugs, such as prednisone, have the same effect as cortisol and adrenaline (epinephrine), causing marginated neutrophils to enter the blood stream. Nervousness will very slightly raise the neutrophil count because of this effect.

A neutrophilia might also be the result of a malignancy. Chronic myelogenous leukemia (CML or chronic myeloid leukaemia) is a disease where the blood cells proliferate out of control. These cells may be neutrophils. Neutrophilia can also be caused by appendicitis and splenectomy.

Primary neutrophilia can additionally be a result of Leukocyte adhesion deficiency.

A "left shift" refers to the presence of increased proportions of younger, less well differentiated neutrophils and neutrophil-precursor cells in the blood. This generally reflects early or premature release of myeloid cells from the bone marrow, the site where neutrophils are generated. A severe neutrophilia with left shift is referred to as a leukemoid reaction. The leukocyte alkaline phosphatase (LAP) score, which refers to the amount of alkaline phosphatase per neutrophil, will increase. In a severe infection, toxic granulation changes happen to the neutrophils.

This can resemble Pelger-Huet anomaly.

The complete blood cell count is a blood panel that includes the overall WBC count and various subsets such as the absolute neutrophil count. Reference ranges for blood tests specify the typical counts in healthy people.

TLC- (Total leucocyte count):

Normal TLC in an adult person is 6000-8000WBC/mm^3 of blood.

DLC- (Differential leucocyte count):

Number/ (%) of different type of leucocyte in per cubic mm. of blood.

Conventionally, a leukocytosis exceeding 50,000 WBC/mm with a significant increase in early neutrophil precursors is referred to as a leukemoid reaction. The peripheral blood smear may show myelocytes, metamyelocytes, promyelocytes, and rarely myeloblasts; however, there is a mix of early mature neutrophil precursors, in contrast to the immature forms typically seen in acute leukemia. Serum leukocyte alkaline phosphatase is normal or elevated in leukemoid reaction, but is depressed in chronic myelogenous leukemia. The bone marrow in a leukemoid reaction, if examined, may be hypercellular but is otherwise typically unremarkable.

Leukemoid reactions are generally benign and are not dangerous in and of themselves, although they are often a response to a significant disease state (see "Causes" below). However, leukemoid reactions can resemble more serious conditions such as chronic myelogenous leukemia (CML), which can present with identical findings on peripheral blood smear.

Historically, various clues including the leukocyte alkaline phosphatase score and the presence of basophilia were used to distinguish CML from a leukemoid reaction. However, at present the test of choice in adults to distinguish CML is an assay for the presence of the Philadelphia chromosome, either via cytogenetics and FISH, or via PCR for the BCR/ABL fusion gene. The LAP (Leukocyte Alkaline Phosphatase) score is high in reactive states but is low in CML. In cases where the diagnosis is uncertain, a qualified hematologist or oncologist should be consulted.

Blood films display a range of abnormalities. A monocyte count of >1x10/L is essential for a diagnosis of CMML. Other features may include; leukocytosis (50% of cases); left shift and dysplasia of monocytes and granulocytes; presence of metamyelocytes, myelocytes and promonocytes; monocytes with hypersegmented/abnormal shaped nuclei, increased cytoplasmic basophilia and/or the presence of cytoplasmic granules; eosinophilia (in cases of CMML with eosinophilia); and spherocytosis (in cases of DCT positive haemolytic anaemia). Platelet counts may be reduced, increased or normal. Haemoglobin levels are usually reduced with normocytic and normochromic red blood cells. Autoantibodies and cold agglutinins may be present and 10% of CMML is DCT positive.

Bone marrow aspirates will display hypercellularity with increased counts of granulocytic and monocytic cells. Bone marrow core biopsies may show a predominance of myelocytic and monocytic cells, abnormal localisation of immature precursors and dysplastic megakaryocytes. Monocytic nodules are a common feature in biopsies.

The phenotypical characteristics of CMML are; CD11b, CD11c, CD14, CD33, CD45 and CD64 seen in 100% of cases; CD13 found in 95% of cases; CD4 found in 76% of cases; HLA-DR found in 71% of cases; CD56 found in 53% of cases; CD2 found in 34% of cases; CD16 found in 29% of cases; CD10 found in 28% of cases; CD23 and CD7 found in 9% of cases; and CD117 found in 5% of cases.

The Düsseldorf score stratifies cases using four categories, giving one point for each; bone marrow blasts ≥5%, LDH >200U/L, haemoglobin ≤9g/dL and a platelet count ≤100,000/uL. A score of 0 indicates a low risk group' 1-2 indicates an intermediate risk group and 3-4 indicates a high risk group. The cumulative 2 year survival of scores 0, 1-2 and 3-4 is 91%, 52% and 9%; and risk of AML transformation is 0%, 19% and 54% respectively.

Although not yet formally incorporated in the generally accepted classification systems, molecular profiling of myelodysplastic syndrome genomes has increased the understanding of prognostic molecular factors for this disease. For example, in low-risk MDS, "IDH1" and "IDH2" mutations are associated with significantly worsened survival.

The WHO has proposed a criterion for diagnosis and classification of MDS that may apply to most cases. However, occasional cases are difficult to classify into defined categories because of one or more unusual features:

- Rare cases with less than 5% blast will present with Auer rods. These cases usually have the features of RAMD.

- Occasionally, cases of MDS present with isolated neutropenia or thrombocytopenia without anemia and with dysplastic changes confined to the single lineage. The term refractory neutropenia and refractory thrombocytopenia have sometimes been used to describe these cases. A diagnosis of MDS in patients with neutropenia or thrombocytopenia without anemia should be made with caution.

- Patients with RA or RAEB occasionally present with leukocytosis or thrombocytosis instead of the usual cytopenia.

Complete remission and long-term survival are more common in children than adults.

Prognosis depends upon the cause. One third of cases is associated with a t(1;22)(p13;q13) mutation in children. These cases carry a poor prognosis.

Another third of cases is found in Down syndrome. These cases have a reasonably fair prognosis.

The last third of cases may be heterogeneous, and carry a poor prognosis.

The morphology of cells was observed by means of bone marrow smear; the immunophenotype was detected by flow cytometry and immunohistochemistry assay.

Blasts more than 20%, with more than 50% of megakaryocytic phenotype.

In blood and bone marrow smears megakaryoblasts are usually medium-sized to large cells with a high nuclear-cytoplasmic ratio. Nuclear chromatin is dense and homogeneous. There is scanty, variable basophilic cytoplasm which may be vacuolated. An irregular cytoplasmic border is often noted in some of the megakaryoblasts and occasionally projections resembling budding atypical platelets are present. Megakaryoblasts lack myeloperoxidase (MPO) activity and stain negatively with Sudan black B. They are alpha naphthyl butyrate esterase negative and manifest variable alpha naphthyl acetate esterase activity usually in scattered clumps or granules in the cytoplasm. PAS staining also varies from negative to focal or granular positivity, to strongly positive staining. A marrow aspirate is difficult to obtain in many cases because of variable degree of myelofibrosis. More precise identification is by immunophenotyping or with electron microscopy (EM). Immunophenotyping using MoAb to megakaryocyte restricted antigen (CD41 and CD61) may be diagnostic.

Routine vaccination against meningococcus is recommended by the Centers for Disease Control and Prevention for all 11- to 18-year-olds and people who have poor splenic function (who, for example, have had their spleen removed or who have sickle-cell disease which damages the spleen), or who have certain immune disorders, such as a complement deficiency.

The term leukemoid reaction describes an increased

white blood cell count, or leukocytosis, which is a physiological response to stress or infection (as opposed to a primary blood malignancy, such as leukemia). It often describes the presence of immature cells such as myeloblasts or red blood cells with nuclei in the peripheral blood.

It may be lymphoid or myeloid.

Studies show a moderate neutrophilia (less than 50%), elevated ESR (greater than 30 mm/h) (90%), and a slight increase in alkaline phosphatase (83%). Skin biopsy shows a papillary and mid-dermal mixed infiltrate of polymorphonuclear leukocytes with nuclear fragmentation and histiocytic cells. The infiltrate is predominantly perivascular with endothelial-cell swelling in some vessels, but vasculitic changes (blood clots; deposition of fibrin, complement, or immunoglobulins within the vessel walls; red blood cell extravasation;inflammatory infiltration of vascular walls) are absent in early lesions.

Perivasculitis occurs secondarily, because of cytokines released by the lesional neutrophils. True transmural vasculitis is not an expected finding histopathologically in SS.

Most patients with "ETV6-ACSL6"-related disease present with findings similar to eosinophilia, hypereosinophila, or chronic eosinophilic leukemia; at least 4 cases presented with eosinophilia plus findings of the red blood cell neoplasm, polycythemia vera; three cases resembled acute myelogenous leukemia; and one case presented with findings of a combined Myelodysplastic syndrome/myeloproliferative neoplasm. Best treatments for "ETV6-ACSL6"-related disease are unclear. Patients with the polycythemia vera form of the disease have been treated by reducing the circulating red blood cell load by phlebotomy or suppressing red blood cell formation using hydroxyurea. Individual case studies report that "ETV6-ACSL6"-associated disease is insensitive to tyrosine kinase inhibitors. Best treatment currently available, therefore, may involve chemotherapy and bone marrow transplantion.

CML accounts for 8% of all leukaemias in the UK, and around 680 people were diagnosed with the disease in 2011.

SCLS is often difficult to recognize and diagnose on initial presentation, and thus misdiagnoses are frequent. The characteristic triad of profound arterial hypotension, hemoconcentration (elevated hematocrit, leukocytosis, and thrombocytosis), and hypoalbuminemia in the absence of secondary causes of shock and infection, requires diagnosis in a monitored, hospital setting during or after an acute episode. The fact that the condition is exceedingly rare – an estimated one per million inhabitants – and that several other diseases exhibit features akin to SCLS, including secondary capillary-leak syndrome or hypoproteinemia, militate against early identification. Preserved consciousness, despite severe shock and hypotension, is an additional and most intriguing clinical manifestation often reported during episodes at hospital admission.