Absolute neutrophil count
Absolute neutrophil count (ANC) is a measure of the number of neutrophil granulocytes[1] (also known as polymorphonuclear cells, PMN's, polys, granulocytes, segmented neutrophils or segs) present in the blood. Neutrophils are a type of white blood cell that fights against infection.
The ANC is calculated from measurements of the total number of white blood cells (WBC), usually based on the combined percentage of mature neutrophils (sometimes called "segs," or segmented cells) and bands, which are immature neutrophils.
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[edit] Clinical significance
A normal ANC is above 1,500 cells per microliter. An ANC less than 500 cells/µL is defined as neutropenia and significantly increases the risk of infection. Neutropenia is the condition of a low ANC, and the most common condition where an ANC would be measured is in the setting of chemotherapy for cancer.
Neutrophilia indicates an elevated count.
[edit] Calculation
![ANC =[(\%neutrophils + \%bands)\times (WBC\times 100)]](http://upload.wikimedia.org/wikipedia/en/math/5/3/9/53966f00a0a695bd710275d70ef3577b.png)
In the above, we assume that the CBC we are reading WBC from is in cells/mL; so the above 100 is a corrective factor to convert to cells/µL. %Neutrophils and %bands should be expressed in their decimal form (e.g. 20% neutrophils would be 0.20).
The unit of ANC is cells per microlitre (abbreviated µL; a microlitre is equal to one cubic millimetre) of blood.
[edit] Ranges
| NCI Risk Category | ANC |
|---|---|
| 0 | Within normal limits |
| 1 | ≥1500 - <2000/mm³ |
| 2 | ≥1000 - <1500/mm³ |
| 3 | ≥500 - <1000/mm³ |
| 4 | < 500/mm³ |
Source: NCI CTC Toxicity scale Version 2.0 [1]
[edit] Related tests
In some cases, a ratio is reported in addition to the sum. This is known as the "I/T ratio" What does "NCI" stand for in NCI Risk Category?[2] (or "I:T ratio").[3]
[edit] References
- ^ Al-Gwaiz LA, Babay HH (2007). "The diagnostic value of absolute neutrophil count, band count and morphologic changes of neutrophils in predicting bacterial infections". Med Princ Pract 16 (5): 344–7. doi:10.1159/000104806. PMID 17709921. http://content.karger.com/produktedb/produkte.asp?typ=fulltext&file=000104806.
- ^ Walliullah SM, Islam MN, Siddika M, Hossain MA, Chowdhury AK (January 2009). "Role of Micro-ESR and I/T Ratio in the Early Diagnosis of Neonatal Sepsis". Mymensingh Med J 18 (1): 56–61. PMID 19182751.
- ^ Russell GA, Smyth A, Cooke RW (July 1992). "Receiver operating characteristic curves for comparison of serial neutrophil band forms and C reactive protein in neonates at risk of infection". Arch. Dis. Child. 67 (7 Spec No): 808–12. doi:10.1136/adc.67.7_Spec_No.808. PMC 1590438. PMID 1519980. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1590438.
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