When running routine blood tests, sometimes abnormal values are flagged by the lab or computer system. Some of these values, while outside of the normal range, are still typical and/or acceptable for people with Down syndrome. Information about MCV, MCH, WBC, ANC, and BUN is provided below. The information is also shown in table form at the bottom of the page.
MCV
What it indicates: Mean corpuscular volume (size of red blood cells)
*Normal range: 78.0 - 100.0
How it can be different in DS: Often high
Why it can be different: 1) In the bone marrow, red blood cells become smaller as they mature. The bone marrow of people with DS may release immature red blood cells, resulting in larger red blood cells in the blood stream. 2) Folic acid metabolism is part of red blood cell production. Enlarged red blood cells may be caused by differences in folic acid metabolism in people with DS.
When to be concerned: If other blood counts (hemoglobin and hematocrit) are abnormal, additional testing may be needed. If other blood counts are normal, an elevated MCV generally does not require further testing.
MCH
What it indicates: Mean corpuscular hemoglobin (amount of hemoglobin in red blood cells)
*Normal range: 26.0 - 34.0
How it can be different in DS: Often high
Why it can be different: Not fully understood but it may be related to differences in folic acid metabolism in people with DS
When to be concerned: If other blood counts are abnormal, additional testing may be needed. If other blood counts are normal, an elevated MCH generally does not require further testing.
WBC
What it indicates: White blood cells (cells that fight infection)
*Normal range: 4,200 - 11,000
How it can be different in DS: Often low
Why it can be different: The bodies of people with DS do not make as many WBCs in the bone marrow.
When to be concerned: Consider checking WBC count annually. Additional testing may be warranted if the WBC is very low, the WBC is dropping, the WBC is low and the person with DS is having recurrent infections, there are abnormal cells, or there is family history of leukemia.
ANC
What it indicates: Absolute neutrophil count (neutrophils are a type of WBC)
*Normal range: 1,800 - 8,000
How it can be different in DS: Often low
Why it can be different: Neutrophils are a specialized type of WBC. Since the bodies of people with DS do not make as many WBCs in the bone marrow, ANC is often low.
When to be concerned: If the number falls below 1,000, additional evaluation should be considered for the person with DS because the risk for infections becomes much higher below 1,000.
BUN
What it indicates: Blood urea nitrogen (a marker of kidney function)
*Normal range: 10-20
How it can be different in DS: Often high
Why it can be different: BUN is often high when a person does not drink enough water. Many individuals with DS we see at the Center do not hydrate adequately and we encourage them to drink more fluids.
When to be concerned: If the only abnormality is an elevated BUN, generally we recommend improved hydration. If there are other abnormal lab values, additional workup may be indicated.
More resources from our online library can be found here.
If you are on a mobile device, the table below is easier to view by turning your mobile device horizontally.
|
Lab
|
What it indicates
|
*Normal range
|
How it can be different in DS
|
Why it can be different
|
When to be concerned
|
|
MCV
|
Mean corpuscular volume
(size of red blood cells)
|
78.0-100.0
|
Often high
|
1. In the bone marrow, red blood cells become smaller as they mature. The bone marrow of people with DS may release immature red blood cells, resulting in larger red blood cells in the blood stream.
2. Folic acid metabolism is part of red blood cell production. Enlarged red blood cells may be caused by differences in folic acid metabolism in people with DS.
|
If other blood counts (hemoglobin and hematocrit) are abnormal, additional testing may be needed. If other blood counts are normal, an elevated MCV generally does not require further testing.
|
|
MCH
|
Mean corpuscular hemoglobin
(amount of hemoglobin in red blood cells)
|
26.0-34.0
|
Often high
|
Not fully understood but it may be related to differences in folic acid metabolism in people with DS.
|
If other blood counts are abnormal, additional testing may be needed. If other blood counts are normal, an elevated MCH generally does not require further testing.
|
|
WBC
|
White blood cells
(cells that fight infection)
|
4,200-11,000
|
Often low
|
The bodies of people with DS do not make as many WBCs in the bone marrow.
|
Consider checking WBC count annually. Additional testing may be warranted if the WBC is very low, the WBC is dropping, the WBC is low and the person with DS is having recurrent infections, there are abnormal cells, or there is family history of leukemia.
|
|
ANC
|
Absolute neutrophil count
(neutrophils are a type of WBC)
|
1,800-8,000
|
Often low
|
Neutrophils are a specialized type of WBC. Since the bodies of people with DS do not make as many WBCs in the bone marrow, ANC is often low.
|
If the number falls below 1,000, additional evaluation should be considered for the person with DS because the risk for infections becomes much higher below 1,000.
|
|
BUN
|
Blood urea nitrogen
(a marker of kidney function)
|
10-20
|
Often high
|
BUN is often high when a person does not drink enough water. Many of our patients do not hydrate adequately and we encourage them to drink more fluids.
|
If the only abnormality is an elevated BUN, generally we recommend improved hydration. If there are other abnormal lab values, additional workup may be indicated.
|
*Each laboratory has its own specific normal values (they are similar from laboratory to laboratory but not the same).
NOTE: This information does not replace the evaluation and recommendations of your health care provider but is intended to provide information to review with your provider.
More resources from our online library can be found here.