InstalabSIBO Malabsorption Panel
Should you take a SIBO Malabsorption Panel test?
This test is most useful if any of these apply to you.
16 biomarkers included
- Vitamins3
- Vitamin B12Small-bowel bacteria can use B12 before you absorb it, so a low level is a malabsorption clue.Why it mattersLow B12 fits small-bowel overgrowth, especially when folate is normal or high.
- Vitamin B9 (Folate)Some overgrown bacteria make folate, so folate can stay normal or rise while B12 falls.Why it mattersNormal or high folate with low B12 points toward bacterial overgrowth, not diet alone.
- Vitamin D (25-hydroxy)Vitamin D travels with fat. A low level can fit fat malabsorption when gut symptoms and other deficiencies line up.Why it mattersLow vitamin D can support a fat-malabsorption pattern, but sun exposure and body weight also move it.
- Red Blood Cells7
- RBC CountCounts red blood cells, showing whether nutrient shortfalls are limiting blood production.Why it mattersA low count supports anemia when hemoglobin and hematocrit are also low.
- HemoglobinMeasures the oxygen-carrying protein in blood and shows whether nutrient loss has become anemia.Why it mattersLow hemoglobin shows the deficiency pattern has already affected oxygen-carrying capacity.
- HematocritShows the share of blood made up of red cells, backing up the hemoglobin read.Why it mattersLow hematocrit confirms the red-cell shortage behind anemia.
- MCVMCV is average red-cell size. It separates large-cell B12 or folate patterns from small-cell iron patterns.Why it mattersHigh MCV points to B12 or folate deficiency; low MCV points to iron deficiency.
- MCHShows how much hemoglobin is packed into the average red cell, often falling with iron deficiency.Why it mattersLow MCH strengthens an iron-deficiency pattern when MCV is also low.
- MCHCShows how concentrated hemoglobin is inside red cells, adding color context to the iron picture.Why it mattersLow MCHC fits pale, iron-starved red cells more than B12 loss.
- RDWRDW shows how uneven red-cell sizes are, catching mixed deficiencies that can make the average size look normal.Why it mattersHigh RDW with normal MCV can reveal iron and B12 problems at the same time.
- Immune Function1
- WBC CountCounts white blood cells, a clue to infection or inflammation that can distort ferritin.Why it mattersA high white count flags infection or inflammation that can lift ferritin into a falsely normal range.
- Blood Clotting1
- Platelet CountCounts clotting cells. Platelets can rise with iron deficiency or inflammation, adding context to iron studies.Why it mattersHigh platelets can back up iron deficiency, inflammation, or both.
- Iron Studies4
- FerritinFerritin tracks stored iron. It often drops before hemoglobin falls when absorption or intake can't keep up.Why it mattersLow ferritin is an early sign that iron reserves are being depleted.
- Total IronShows the iron circulating now, which can fall from poor intake, poor absorption, blood loss, or inflammation.Why it mattersLow iron supports deficiency when ferritin and saturation point the same way.
- Transferrin SaturationShows how much iron-carrying capacity is filled, tying current iron supply to the body's demand.Why it mattersLow saturation means too little usable iron is reaching blood-making tissue.
- TIBCMeasures iron-carrying capacity. It usually rises when the body is trying to capture more iron.Why it mattersHigh TIBC with low ferritin favors true iron deficiency over inflammation alone.
About SIBO Malabsorption Panel
Small intestinal bacterial overgrowth does more than make you bloated. Bacteria can crowd the part of the gut where you absorb B12, iron, and fat. If they get there first, your blood may show the loss before you feel it.
This panel doesn't diagnose the overgrowth. Breath testing is the usual noninvasive way to look for that. This panel asks a different question: are you already losing nutrients or changing your blood counts in a pattern that fits poor absorption?
What This Panel Reveals
Start with the red cells. When B12, folate, or iron runs short, the bone marrow still makes cells, but the cells come out changed. Hemoglobin and hematocrit show how much oxygen-carrying red-cell mass you have. MCV is the average red-cell size. Large cells often point toward B12 or folate. Small cells often point toward iron.
The B12 and folate pair is the most distinctive part of the panel. In bacterial overgrowth, some bacteria use B12. Some make folate. So the pattern can be low B12 with normal or high folate. High folate is often the more consistent signal, while frank B12 deficiency is less common. That's not proof. It is a clue that diet alone may not explain the result.
The iron studies separate depleted iron stores from the look-alikes. Ferritin is your iron savings account. It usually drops before anemia appears. TIBC is how much iron your blood could carry, and transferrin saturation is how much of that carrying space is filled. In plain iron deficiency, ferritin and saturation tend to fall while TIBC rises. That pattern says iron is truly running short. It doesn't tell you why. Poor absorption and blood loss can look the same. In typical overgrowth, iron changes are often subtle; overt iron loss is more likely when there is small-bowel injury or altered anatomy.
Vitamin D is here for a different reason. It travels with fat. Overgrowth can disrupt bile, and you need bile to absorb fat. So a low vitamin D can fit a fat-absorption problem, but it is a weak clue by itself because sun exposure and body weight move it too.
How to Read Your Results Together
No single result here proves bacterial overgrowth. The useful signal is the combination. RDW is the spread of red-cell sizes. It matters when mixed deficiencies pull cell size in opposite directions.
| Pattern | What It Suggests |
|---|---|
| Low B12, normal or high folate | A pattern that fits bacterial overgrowth: some bacteria use B12 while others make folate. |
| Low ferritin, low transferrin saturation, high TIBC | True iron deficiency. The cause could be poor absorption, blood loss, or both. |
| High MCV | Large red cells point toward B12 or folate deficiency. |
| Normal ferritin with low transferrin saturation and high white cells or platelets | Inflammation may be making ferritin look safer than it is. |
| Normal MCV, high RDW | A mixed deficiency can hide inside a normal average cell size. Check the full iron and B12 pattern. |
That last row is easy to miss. A normal MCV can hide large B12-poor cells and small iron-poor cells averaging each other out. RDW catches the spread.
When Results Can Be Misleading
Ferritin has a flaw. It rises with inflammation, infection, or injury. That can lift a truly low ferritin into the normal range. Gut inflammation can do the same. High white cells or platelets can hint at this, though a dedicated inflammation marker like C-reactive protein is a more reliable check. Either way, when inflammation is present a normal ferritin is less reassuring, and transferrin saturation carries more weight.
None of these markers is specific to small-bowel overgrowth. Celiac disease, autoimmune B12 absorption problems, poor diet, blood loss, and pancreatic disease can produce the same deficiencies. In one study of 162 adults having hydrogen breath testing, low vitamin D and blood-count differences did not stay linked to overgrowth after age, sex, and body weight were accounted for. Read this panel as evidence of consequences, not proof of a cause.
What to Do with Your Results
If B12 is low or borderline, check methylmalonic acid. This follow-up marker often rises when B12 isn't working well, though short-bowel problems and kidney disease can also move it. If iron studies point to deficiency, look for the source: poor absorption, celiac disease, and blood loss are all possible. If the overall pattern fits overgrowth, use a hydrogen and methane breath test to look for it directly. After treatment or nutrient replacement, retest the abnormal markers. The direction matters more than a single value: B12, ferritin, and red-cell size should move toward recovery.