Last reviewed: May 12, 2026 Last updated: May 12, 2026

Written by: Jay Hastings , CEO of PlexusDx

Jay Hastings is the CEO of PlexusDx, a precision health company focused on genetic testing, blood biomarker insights, and personalized wellness recommendations. He has more than 20 years of experience across healthcare innovation, genomics, laboratory operations, healthcare investing, and strategic finance. His work has included scaling healthcare startups, leading CLIA lab integrations, and helping expand consumer access to precision health tools.

Medically reviewed by: Jayden Lee, PharmD, EMBA

Jayden Lee, PharmD, EMBA, is the PlexusDx Medical Science Liaison with a PharmD and MBA specializing in pharmacogenomics and clinical product development, with a proven ability to bridge the gap between genomic research and practical patient outcomes. Dr. Lee has more than 10 years of professional experience in clinical pharmacy, academia, and research.

This article is part of the PlexusDx Education Hub — your resource for evidence-based guidance on blood testing & biomarkers. Browse all Blood Testing & Biomarkers education

A low neutrophil count — clinically called neutropenia — means your blood carries fewer of the white cells that form your first line of defense against bacterial and fungal infection. It is often discovered by accident on a routine complete blood count, and for many people it is mild and harmless. Understanding what drives it, and the genetic factors involved, helps you have a more informed conversation with your provider.

What Neutrophils Do and What Neutropenia Means

Neutrophils are the most abundant white blood cell in circulation, typically 40 to 60 percent of the total. They are the rapid responders of the innate immune system, engulfing bacteria and releasing enzymes that destroy pathogens. Neutropenia is generally defined as an absolute neutrophil count below 1,500 cells per microliter, with severity graded from mild to severe. The lower the count, the higher the infection risk.

Common Causes of Low Neutrophils

Neutropenia has many possible drivers. Acquired causes include viral infections, certain medications, chemotherapy and radiation, autoimmune conditions such as lupus, nutritional deficiencies in vitamin B12 or folate, and bone marrow disorders. Some people have chronic idiopathic neutropenia with no identifiable trigger. A smaller group has an inherited form present from early life. Because the causes range from trivial to serious, a persistently low count deserves medical evaluation rather than self-interpretation.

Symptoms and When It Matters

Neutropenia itself usually causes no symptoms — the number is often the only clue. When counts fall low enough to raise infection risk, warning signs can include recurrent fevers, mouth ulcers, sore throats, gum inflammation, and skin infections that are slow to heal. Fever in someone with severe neutropenia is treated as urgent. Mild neutropenia, by contrast, may simply be monitored over time.

The Genetic Factors Behind Low Neutrophils

Genetics shapes baseline neutrophil counts in ways that are increasingly well mapped. The most common inherited pattern is benign ethnic neutropenia, tied to a variant in the ACKR1 gene (the Duffy antigen, rs2814778). The Duffy-null genotype is common in people of African, Middle Eastern, and West Indian ancestry and produces a lower-but-normal neutrophil set point with no increased infection risk — an important distinction, because it is frequently mistaken for a problem.

Rarer inherited neutropenias trace to different genes. Variants in ELANE cause cyclic and severe congenital neutropenia, while changes in HAX1 underlie the classic Kostmann form. Nutrient-processing genes matter too: MTHFR C677T influences folate metabolism, and because folate and B12 are required for healthy blood-cell production, methylation-pathway genetics can intersect with counts when intake is marginal. These variants describe tendencies in your biology — they are not, on their own, a diagnosis.

How Low Neutrophils Are Evaluated

A provider confirms neutropenia by repeating the complete blood count and reviewing the trend rather than a single value. Depending on the picture, evaluation may add tests for infection, autoimmune markers, nutrient levels, a peripheral blood smear, and — in select cases — a bone marrow examination or targeted genetic screening for inherited forms. The goal is to separate a harmless genetic set point from a condition that needs treatment.

Where Pathway-Level Genetic Insight Fits

Knowing your genetics does not replace that workup, but it adds context. The PlexusDx Precision Peptide Genetic Test looks at pathway-level biology across many systems, and reporting genetic tendencies is what precision-health tools do well. It is education about your baseline biology — a map, not a verdict — meant to inform the questions you bring to a qualified provider.

Frequently Asked Questions About Low Neutrophils

Is a low neutrophil count always dangerous?

No. Many people, especially those with the Duffy-null ACKR1 genotype, have a naturally lower set point with no added infection risk. Danger depends on how low the count is and the underlying cause, which is why a provider interprets the trend rather than a single reading.

Can genetics explain why my neutrophils run low?

Sometimes. Benign ethnic neutropenia linked to the ACKR1 Duffy variant is the most common inherited pattern, and rarer genes like ELANE or HAX1 cause congenital forms. Genetic factors describe tendencies in your biology; a provider still confirms the cause with blood work.

Does the Precision Peptide Genetic Test diagnose neutropenia?

No. The test does not diagnose, treat, or manage neutropenia or any condition. It offers pathway-level genetic context about your biology for education. Diagnosis of a low neutrophil count requires a complete blood count and evaluation by a qualified healthcare provider.

Curious about your own peptide-pathway genetics? The Precision Peptide Genetic Test analyzes 14 pathways, 49 peptides, 150+ genetic insights — pathway-level context you can bring to your healthcare provider. It is educational insight into your biology, not a diagnosis or a prescription.

This article is part of the PlexusDx Education Hub. Browse all Blood Testing & Biomarkers education

The Precision Peptide Genetic Test analyzes how your genes influence peptide-related biological pathways. It does not recommend, prescribe, or determine which peptides you should use. Consult a qualified healthcare provider before beginning any peptide protocol.

Medical and Editorial Standards

Medical review process: This article was reviewed for medical accuracy, scientific clarity, evidence alignment, and appropriate discussion of genetics, medications, supplements, biomarkers, and health-related claims.

Sources and evidence: PlexusDx educational content is developed using peer-reviewed research, clinical literature, reputable medical references, and, where applicable, public health or regulatory guidance. References are included at the end of the article when scientific, medical, or health-related claims are discussed.

Commercial transparency: PlexusDx offers genetic testing, blood biomarker testing, personalized supplement recommendations, and related precision wellness services. Product mentions are intended to help readers understand available options and should not be interpreted as medical advice.

Important disclaimer: PlexusDx educational content is for informational purposes only and should not be used as a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making decisions about medications, supplements, genetic testing, lab testing, or health-related care.