What diagnostic tests might a doctor order to determine the cause of iron deficiency in adults?

To determine the cause of iron deficiency in adults, a doctor may order a series of diagnostic tests, usually starting with basic blood work. These tests aim to confirm iron deficiency, assess its severity, and then investigate the underlying cause, especially if internal bleeding is suspected. It is important to identify the cause because iron deficiency can be an indicator of other medical conditions that require treatment.

Initial Blood Tests

When iron deficiency is suspected, a doctor usually orders several blood tests to assess iron levels in the body. This includes a Complete Blood Count (CBC), which measures the level of hemoglobin—the protein that carries oxygen in red blood cells—which is affected by iron deficiency [1]. Blood iron levels and ferritin levels are also measured; ferritin is a protein that stores iron in the body, and low ferritin levels indicate depleted iron stores [1]. These tests help confirm a diagnosis of iron deficiency anemia [3].

Investigating Sources of Bleeding

Blood loss is one of the most common causes of iron deficiency in adults [3]. Therefore, after confirming iron deficiency, the doctor focuses on looking for any sources of bleeding. This may include gastrointestinal bleeding, which can result from conditions such as inflammatory bowel disease, ulcers, colon cancer, or other gastrointestinal diseases like celiac disease [3]. Bleeding can also occur due to the regular use of certain medications, such as aspirin or non-steroidal anti-inflammatory drugs (NSAIDs) [3].

Gastrointestinal Examinations

If the doctor suspects gastrointestinal bleeding as the cause of iron deficiency, they may recommend specialized gastrointestinal examinations. These tests may include an Upper Endoscopy to examine the esophagus, stomach, and duodenum, and a Colonoscopy to examine the large intestine. These procedures allow the doctor to see any areas of bleeding, inflammation, or tumors that may be causing blood loss [3]. In some cases, other tests, such as fecal tests to detect occult blood, may be needed.

Additional Considerations and Other Causes

In addition to bleeding, there are other causes of iron deficiency that may require further testing. These causes can include problems with iron absorption from food, which can result from conditions like celiac disease, ulcerative colitis, Crohn's disease, or H. pylori bacterial infection [3]. Some stomach and intestinal surgeries, including weight-loss surgeries, can also affect iron absorption [3]. In rare cases, certain genetic conditions may affect iron absorption or make it harder to stop bleeding [3]. It is important to discuss your full medical history and symptoms with your doctor to determine the most appropriate tests for your individual case. You can learn more about the importance of searching for the source of bleeding in iron deficiency cases by visiting Iron deficiency in adults: The importance of searching for the source of bleeding (Arabic).

Medical references

• Iron
• Anemia Iron-Deficiency Anemia