TL; DR
The normal anion gap is usually around 8–12 mEq/L. When this gap is less than 8, it is a low anion gap. An anion gap test costs around $13 and $40 in the U.S.
What is a Low Anion Gap
There are fewer negatively charged particles in the blood than expected. It is called a low anion gap.
When doctors run routine blood tests, one value they sometimes check is the anion gap. It’s not a disease on its own. Rather, it is a calculation that helps assess the balance of charged particles (electrolytes) in the blood. Our blood contains positively charged particles like sodium and negatively charged particles like chloride and bicarbonate. The anion gap is calculated using these values. It analyses whether the balance between positive and negative charges looks normal. Typically, the normal range falls between 8 and 12 mEq/L, although this can vary slightly depending on the laboratory.
A low anion gap means that this balance has shifted. Specifically, you can expect fewer negatively charged particles as well. Think of it as a scale that usually balances positive and negative charges. If the number comes back low, it suggests that either negative charges have decreased, positive charges have increased, or the test result may not be entirely accurate.
Anion Gap Calculation
If you know, ‘What is an anion? (a negatively charged ion).’ Then you will probably understand this easily.
The most common formula is:
Anion Gap = Sodium (Na⁺) – (Chloride (Cl⁻) + Bicarbonate (HCO₃⁻))
These values come from a routine or anion gap blood test called a basic metabolic panel (BMP).
Low Anion Gap Causes
The various factors that make an anion gap low are:
1. Low Albumin
One of the most common reasons for a low anion gap is low albumin levels. Albumin is a protein made by the liver, and it carries a negative charge in the bloodstream.
Low albumin can occur in conditions such as:
- Liver disease (where albumin production is reduced)
- Kidney disorders (where albumin may be lost in urine)
- Malnutrition (where the body lacks enough protein to produce it)
- Chronic illnesses
2. Extra Positive Proteins in the Blood
Another possible cause of low anion gap is the presence of extra positively charged proteins in the blood. Some of these proteins carry a positive charge. When there is an increase in these positively charged proteins, the overall charge balance in the blood shifts. As a result, the anion gap appears lower because the formula reflects this increase in positive particles.
3. High Levels of Certain Substances
In some cases, high levels of specific substances can also reduce the anion gap. For instance, lithium. It is commonly used to treat certain psychiatric conditions and can increase the number of positively charged particles in the blood. Similarly, bromide can interfere with lab measurements and alter the balance of charges.
4. Lab Errors
Finally, it’s important to consider the possibility of a laboratory error. Sometimes a low anion gap result does not reflect a true imbalance in the body. But instead, it occurs due to testing machine issues, calibration problems, or sample handling errors. Because of this, doctors often repeat the test to confirm the result before investigating further. Rechecking ensures that the low value is accurate and not simply a technical mistake.
What are Low Anion Gap Symptoms
The symptoms, if present, are usually related to the underlying condition that caused the low value, not the anion gap itself.
Here are the major symptoms you’ll see:
| Symptoms related to blood disorders | Symptoms related to lithium or similar substances |
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What Cancers Cause Low Anion Gaps?
Various cancers release abnormal proteins that change the electrical balance in the blood. The major cancer causes of making anion gap low are:
1. Multiple Myeloma (Most Common Cancer Cause)
It is a type of blood cancer that affects plasma cells in the bone marrow. In this condition, the body makes large amounts of abnormal proteins called M proteins.
These abnormal proteins often have a positive charge. When too many of them build up in the blood, they increase the number of positive particles. Since the anion gap is based on the balance between positive and negative charges, having extra positive proteins makes the anion gap value lower than normal.
Doctors may suspect multiple myeloma if a low anion gap appears along with:
- Bone pain
- Fatigue or anemia
- Frequent infections
- Kidney problems
- High total protein levels in blood tests
2. Other Plasma Cell Disorders
Other related conditions can also cause a low anion gap, including:
- Monoclonal gammopathy of undetermined significance (MGUS)
- Waldenström macroglobulinemia
These conditions also involve abnormal protein production, which can affect the anion gap similarly.
How to Treat Low Anion Gap
If you’re thinking, ‘Should I be worried if my anion gap is low? ' then the straight answer is no. That said, there are certain important actions you should take next.
1. Confirm the Result Before Taking Action
The first and most important step is to make sure the low anion gap result is correct. Sometimes, the value appears low because of a lab or machine error. To avoid confusion, doctors usually repeat the anion blood test to confirm the result. They also look closely at the individual electrolyte levels, sodium, chloride, and bicarbonate, to check if any unusual readings affected the calculation. In addition, albumin levels are tested because low albumin can naturally lower the anion gap.
2. Correct Low Albumin Levels (Most Common Cause)
Low albumin is the most common reason for a low anion gap, so treatment usually focuses on correcting the low albumin level. Albumin can drop for several reasons, such as:
- Liver disease - Management may include medications, lifestyle changes (such as avoiding alcohol), and monitoring liver function.
- Kidney disorders - Doctors may prescribe medications to reduce protein loss, control blood pressure, or manage underlying conditions like diabetes.
- Malnutrition - Dietary improvements and nutritional supplementation are recommended.
- Chronic illness or infections - Treating the primary disease can gradually restore albumin levels.
In severe cases, doctors may give albumin through an IV in the hospital. However, this is usually done only in specific situations and is not needed for most mild cases.
3. Evaluate and Treat Blood Protein Disorders
If doctors suspect that there are extra positively charged proteins in the blood, they will run additional tests to find out why.
Treatment may include:
- Targeted therapy
- Chemotherapy
- Immunotherapy
- Steroids or other supportive treatments
As the abnormal protein levels decrease with treatment, the anion gap usually normalizes.
4. Review Medications and Substance Exposure
Certain medications or substances, such as lithium, can lower the anion gap by increasing positive charges in the blood. If a medication is suspected:
- Blood levels of the drug may be checked.
- The dosage may be adjusted.
- In some cases, the medication may be temporarily stopped or switched.
5. Correct Associated Electrolyte Imbalances
Sometimes a low anion gap occurs alongside other electrolyte disturbances. In such cases, doctors focus on restoring overall electrolyte balance. This may involve:
- Intravenous fluids
- Careful correction of sodium or chloride levels
- Monitoring acid–base balance
6. Ongoing Monitoring and Follow-Up
After addressing the suspected cause, regular monitoring is important. Doctors may repeat blood tests to track:
- Electrolyte levels
- Albumin levels
- Kidney and liver function
How to Raise Anion Gap Naturally
- Eat enough protein (eggs, beans, dairy, nuts, lean meat).
- Avoid excess alcohol to support liver health.
- Drink adequate water and stay well hydrated.
- Manage conditions like diabetes or kidney problems.
- Maintain a healthy body weight.
What Are Your Payment Options After a Low Anion Gap Diagnosis
A low anion gap result should be discussed with a qualified healthcare provider who can determine if further evaluation or treatment is needed. If prescriptions or additional care are recommended, costs may vary. Exploring payment solutions in advance can help ease financial concerns and ensure timely treatment.
1. Health Insurance
If you have health insurance in the U.S., it usually helps pay for:
- Blood tests (electrolytes, albumin, protein studies)
- Doctor visits
- Imaging and specialist care
- Treatments if an underlying condition is found
Different plans vary; therefore, check your insurance card or contact your provider for details.
2. Payment Plans
Hospitals and some doctor offices may offer healthcare payment plans to spread the cost over months. These plans basically vary from provider to provider. Moreover, the interest rates and terms and conditions are different.
A payment plan can be used for:
- Doctor visits
- Blood tests (electrolytes, albumin, protein studies)
- Specialist consultations (e.g., hematologist)
- Imaging (if ordered)
- Treatments related to the cause (e.g., medicines, infusions)
Denefits Payment Plans: Making Medical Treatments Affordable
Denefits offers flexible payment plans that can help patients manage the cost of medical care related to a low anion gap. While a low anion gap itself is not something you are billed for, you may need to pay for doctor visits, blood tests, specialist consultations, or treatment to identify and address the underlying cause.
If your healthcare provider uses Denefits, they can set up a payment plan that allows you to split the total cost into affordable monthly chunks instead of paying the full amount upfront. Payments are typically scheduled automatically, making the process simple.
If someone qualifies for public health programs:
- Medicaid (for low-income) generally covers lab tests and doctor care.
- Medicare (for age 65+ or certain disabilities) covers much of the evaluation and treatment. However, you may pay parts like deductibles or premiums.
4. Out-of-Pocket
This should be your last resort if you don’t find any other way to pay. The major options include:
- Direct pay labs – Many labs (Quest Diagnostics, LabCorp, etc.) offer blood tests at set cash prices.
- Clinic pricing – Some clinics post prices for office visits and procedures.
- Negotiated rates – Ask for a self-pay discount or payment plan.
The Final Words
An unexpected lab result can feel alarming, but a low anion gap alone is not a diagnosis. It’s simply a clinical marker that doctors use alongside other findings. In many cases, the result may not indicate a serious problem. Your healthcare provider will determine whether additional testing or treatment is necessary based on your overall health.
If follow-up care is recommended, take time to review your treatment plan and understand the available financing options. Being informed about both your health and your payment choices can make the process smoother and more manageable.
FAQs
1. How Is a Low Anion Gap and Autoimmune Disease Related?
Autoimmune diseases can sometimes lower albumin levels due to chronic inflammation, which may reduce the anion gap. The connection is usually indirect rather than a direct cause.
2. Should I Be Worried if My Anion Gap Is Low?
In most cases, no. A low anion gap is usually not dangerous by itself, but you should follow up with your healthcare provider to rule out underlying causes.
3. What Medications Can Cause a Low Anion Gap?
Lithium is the most common medication linked to a low anion gap. Rarely, substances like bromide-containing drugs can also affect the result.
4. What Is the Difference Between Low Vitamin D and Low Anion Gap?
Low vitamin D is a nutrient deficiency affecting bone and immune health, while a low anion gap is a lab calculation related to electrolyte balance—they are not directly related.
5. How To Raise an Anion Gap?
You don’t raise the anion gap directly; instead, doctors treat the underlying cause, and the value usually returns to normal on its own.
6. What It Means When an Anion Gap Is High?
A high anion gap means there is excess acid in the blood, usually due to a buildup of unmeasured acids. It can occur in conditions like diabetic ketoacidosis, kidney failure, or severe infections and requires medical evaluation.
