Labs

Labs (1 of 40 slides)

Labs (2 of 40 slides)

Let’s begin with the patient’s CBC:

WBC (109/L)Hb (g/dL)MCV (fL)PLT (109/L)
3.814.580211

What’s what: WBC, white blood cell count; Hb, hemoglobin; MCV, mean cell volume; MCHC, mean cellular hemoglobin concentration; RDW-SD, red cell distribution width-standard deviation; platelets, PLT; Normal values: WBC 5-10 x 109/L, RBC 4-6 x 1012/L, Hb 12-16 g/dL, Hct 35-47%, MCV 80-100 fL, MCHC 32-36 g/dL, RDW-SD < 45%, platelets (PLT) 150-450 x 109/L

The CBC reveals leukopenia (defined by white cell count < 4.5 x 109/L) and a low normal MCV.

Labs (2 of 40 slides)

Let’s begin with the patient’s CBC:

WBC (109/L)Hb (g/dL)MCV (fL)PLT (109/L)
3.814.580211

What’s what: WBC, white blood cell count; Hb, hemoglobin; MCV, mean cell volume; MCHC, mean cellular hemoglobin concentration; RDW-SD, red cell distribution width-standard deviation; platelets, PLT; Normal values: WBC 5-10 x 109/L, RBC 4-6 x 1012/L, Hb 12-16 g/dL, Hct 35-47%, MCV 80-100 fL, MCHC 32-36 g/dL, RDW-SD < 45%, platelets (PLT) 150-450 x 109/L

The CBC reveals leukopenia (defined by white cell count < 4.5 x 109/L) and a low normal MCV.

Whenever the WBC count is abnormal, we should order a white cell differential. This showed:

Absolute neutrophil count 0.91 x 109/L, absolute lymphocyte count 2.46, absolute monocyte count 0.36, absolute basophil count 0.02, absolute eosinophil count 0.03.

A previous CBC from 2 years ago showed:

WBC (109/L)Hb (g/dL)MCV (fL)PLT (109/L)
4.514.580227

The MCV is on the low side. What are possible explanations?

a
Thalassemia minor
b
Iron deficiency
c
Hb C trait
d
Pernicious anemia
e
Hypothyroidism

What is the prevalence of BEN in persons of African descent?

a
25–50% persons of African descent
b
4% persons of African descent
c
70-75% persons of African descent

What other ethnicities have an increased incidence of BEN?

a
Middle Eastern descent
b
West Indian descent
c
Irish descent
d
African descent
e
Yemenite Jews

The peripheral smear is unremarkable. What other labs would you like to order?

a
None, simply wait and watch
b
ANA and dsDNA
c
Haptoglobin

Once the diagnosis is confirmed, this entity does not require monitoring or hospital admission. This type of neutropenia does not require any treatment, including no antimicrobial prophylaxis or G-CSF. These individuals are healthy subjects, and are expected to have a lower ANC than current reference ranges without concern for increased infections. in asymptomatic persons of African descent with mild neutropenia, extensive work-up is not necessary

perform serial CBC panels over a period of days or weeks to establish trend in neutrophil count and chronicity

  • ideally confirm neutropenia with 3 CBCs per week over a 6-week period in order to account for physiological fluctuations

  • outpatient investigations of ANC between 1 × 109/L and 1.5 × 109/L in individuals of certain ethnicities (African, Middle Eastern, and Caribbean) not recommended outside setting of recurrent infections, fever, recurrent or severe oral ulcers, lymphadenopathy, splenomegaly or other cytopenia(s)
  • outpatient investigations of ANC between 0.5 × 109/L and 1 × 109/L recommended in individuals of certain ethnicities to rule out secondary causes of neutropenia
  • monitoring ANC after diagnosis of benign ethnic neutropenia is not necessary

Other labs to consider according to cause of neutropenia:

Evaluation of suspected congenital neutropenia

establish chronic neutropenia by evaluating complete blood count (CBC) with differential over a period of days or weeks to confirm trend of neutropenia lasting ≥ 3 months, or by documenting low counts in past

assess severity of neutropenia and presence of recurrent or severe infections

if using genetic sequencing to confirm diagnosis of severe congenital neutropenia (SCN), consider sequencing ELANE first (mutations in ELANE are most common) unless family history, physical examination, or laboratory testing results suggest other diagnosis 

  • if SCN is suspected, assess for ELANE and HAX1 gene mutations
  • if cyclic neutropenia is suspected1
    • perform serial complete blood counts with differential ≥ twice weekly for a minimum of 4-6 weeks to establish cyclic pattern
    • assess for ELANE gene mutation