Blood Test Markers
Explainers on the markers that show up in routine bloodwork — what each number means, how to read reference ranges, and which trends matter more than a single result.
Blood Test MarkersNutritional DeficiencyWhat does low vitamin D mean? — A plain-English guide
Low vitamin D usually means your body's stores of the sunshine vitamin have dipped — common in winter and indoors. Here's what the marker measures and what a low reading does and doesn't mean.
4 min read
Thyroid HealthHypothyroidismWhat does high TSH mean? — A plain-English guide
High TSH usually means your brain is nudging your thyroid to work harder. Here's what the marker measures, why it matters, and what to do next.
4 min read
Cardiovascular HealthBlood Test MarkersWhat does high homocysteine mean?
A high homocysteine means more of this amino acid is building up in your blood than your body usually keeps around. Most of the time that happens because the B-vitamins that normally recycle it — B12, folate, and B6 — are running low. On its own it doesn't diagnose anything. It's one signal that, read in context, can flag a B-vitamin gap or add a little color to your cardiovascular picture. That's exactly why it's worth understanding rather than fearing.
4 min read
ALTBlood Test MarkersWhat does high AST mean?
A high AST means there's more of an enzyme called aspartate aminotransferase in your blood than usual — often because some of the cells that hold it have released it. Those cells live in your liver, but also in your muscles, your heart, and your red blood cells. It's a common and usually mild finding, and on its own it rarely tells the whole story. What it means depends on how high it is, what's sitting next to it on the panel, and where it's been heading over time.
7 min read
B12 DeficiencyVitamin B12What does low B12 mean?
Low B12 means your body doesn't have enough vitamin B12 — also called **cobalamin** — circulating to keep up with what your cells need it for. That's a long list: making red blood cells, copying DNA, and maintaining the myelin sheath that wraps your nerves so signals travel cleanly. When B12 runs low, those processes get sloppy. You feel it before the bloodwork shows it.
6 min read