---
title: "What does a low Total IgA mean?"
type: biomarker-interpretation
url: "https://www.test-well.com/biomarkers/total-iga/low"
biomarker: Total IgA
direction: low
reference_range:
  - "age 18+: 70.0 – 400 mg/dL"
reviewed_at: 2026-09-08
review_status: reviewed
date_published: 2026-09-05
---

# What does a low Total IgA mean?

> Low total IgA — including selective IgA deficiency, the most common primary immune deficiency at about 1 in 500 people — is often found by accident and often harmless, though it can mean more sinus and chest infections, and it matters for celiac testing: the standard tTG-IgA test reads falsely normal when IgA is low, so IgG-based celiac tests are used instead. Some medications and protein-losing conditions lower it too.


## What is the normal range for Total IgA?

- age 18+: 70.0 – 400 mg/dL

IgA deficiency can affect interpretation of other antibody tests (like tTG-IgA for celiac).

## What are the common causes of low Total IgA?

1. Selective IgA deficiency (inherited)
2. Common variable immunodeficiency and other primary immune deficiencies
3. Medications: some anticonvulsants, sulfasalazine, gold, penicillamine
4. Protein-losing conditions, nephrotic syndrome
5. Children under 4 (normal developmental low)

## What symptoms go with low Total IgA?

- Often none
- Recurrent sinus, ear and chest infections, chronic diarrhea
- Higher rates of celiac disease and autoimmune conditions

## What do clinicians usually check next?

- If testing for celiac: tTG-IgG or deamidated gliadin IgG instead of the IgA test
- IgG and IgM; immunology referral if infections are frequent or IgG is also low
- Inform clinicians before any blood transfusion (rare anti-IgA reactions)

## How do you recheck Total IgA?

| Test or panel | Type | Price | Fasting | Results |
| --- | --- | --- | --- | --- |
| [Gut Health Panel](https://www.test-well.com/tests/gut-health-panel) | Panel (5 tests) | $129.99 | No | 3–7 business days |
| [Celiac Disease Panel](https://www.test-well.com/tests/celiac-disease-comprehensive) | Test | $124.99 | No | 3–7 business days |

Plus one $6 lab processing fee per order; physician authorization included.

## Common questions

### Why does low IgA affect my celiac test?

The usual celiac screen measures an IgA antibody. If you make little IgA overall, the test comes back low even with celiac disease. Labs run IgG-based tests instead when total IgA is low.

## Related

- [What does a high Total IgA mean?](https://www.test-well.com/biomarkers/total-iga/high)
- [Total IgA reference ranges](https://www.test-well.com/biomarkers/total-iga)
- [hs-CRP reference range](https://www.test-well.com/biomarkers/hs-crp)
- [ESR reference range](https://www.test-well.com/biomarkers/esr)
- [C-Reactive Protein reference range](https://www.test-well.com/biomarkers/c-reactive-protein)

## Sources

- [Mayo Clinic Labs](https://www.mayocliniclabs.com/test-catalog/overview/8158)
- [MedlinePlus (NIH) — Immunoglobulins Blood Test](https://medlineplus.gov/lab-tests/immunoglobulins-blood-test/)

---

Medically reviewed by Youmna DiStefano, MD (Medical Reviewer, TestWell); last reviewed 2026-09-08. Review policy: https://www.test-well.com/editorial-policy

Canonical page: https://www.test-well.com/biomarkers/total-iga/low
Machine-readable catalog: https://www.test-well.com/api/catalog.json · MCP server: https://www.test-well.com/mcp · Overview for agents: https://www.test-well.com/llms.txt

Prices are cash-pay, in USD, and include physician authorization; every order adds one flat $6 lab processing fee. Educational content is not a diagnosis — discuss results with a clinician.