Differential white blood cell count

Changes in total and differential white blood cell counts... 

Maria s medical notes show that she has mild rheumatoid arthritis (an autoimmune disease), the condition is not severe and her joint pain is well controlled by a non-steroidal anti-inflammatory drug (NSAID), taken twice a day. She is not trying to diet and apparently has a well-balanced food intake, but reports that she has recently had several minor stomach upsets and colds. A blood sample is taken for analysis, including a differential white blood cell count. 

Q6 What is the diagnostic value of a differential white blood cell count ... 

Patients older than 40 years of age should receive a pretreatment electrocardiogram before starting clomipramine. In patients with liver disease, baseline and periodic liver function tests are recommended when clomipramine is used. If clomipramine is given concurrently with sympatholytic antihypertensive agents, blood pressure should be regularly monitored. Patients receiving clomipramine who develop fever and sore throat should have leukocyte and differential white blood cell counts assessed to evaluate for agranulocytosis. 

The evidence that the concurrent use of ACE inhibitors and azathioprine increases the risk of leucopenia is also limited. However, the UK manufacturer of captopril recommends that captopril should be used with extreme caution in patients receiving immunosuppressants, especially if there is renal impairment. They advise that in such patients differential white blood cell counts should be performed before starting captopril, then every 2 weeks in the first 3 months of treatment, and periodically thereafter. The UK manufacturers of a number of other ACE inhibitors also state in their prescribing information that the use of ACE inhibitors with cytostatic or immunosuppressive drugs may lead to an increased risk of leucopenia. For other potential interactions with ACE inhibitors that might lead to an increased risk of leucopenia, see also ACE inhibitors + Allop-urinoE, p.l3, and ACE inhibitors + Proeainamide , p.33. 

General diagnostic tests include urine toxicology screening for psychoactive drugs and metabolites of cocaine. It has additionally suggested reticulocyte count, urinalysis, complete blood count, platelets and differential white blood cell count. 

Anemia, leukopenia, macrocytosis or an abnormal differential white blood cell count should alert the physician to further investigate and/or refer the patient if repeat tests confirm the abnormalities. If routine screening deteds an abnormality, follow-up tests which may be helpful in establishing the etiology of the abnormality are the peripheral blood smear and the reticulocyte count. 

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