Magnesium (whole blood) - the stable total image
This blood test measures the amount of magnesium in whole blood. Magnesium is an essential mineral involved in hundreds of processes in the body. Among other things, it plays a role in muscle and nerve function, energy metabolism, and various enzymatic processes.
Why test for magnesium?
A prolonged magnesium deficiency can be associated with symptoms such as fatigue, muscle cramps, muscle twitching, or restless legs. Magnesium also plays a role in the normal functioning of the nervous system and heart rhythm.
Magnesium is found in many different foods. However, magnesium status can be influenced by factors such as diet, intestinal absorption, certain medications, increased loss, or an increased need.
What does the whole-blood magnesium test measure?
Whole blood consists of:
plasma;
red blood cells (erythrocytes);
white blood cells (leukocytes);
platelets (thrombocytes).
This test measures magnesium in the whole blood sample. This distinguishes it from a magnesium test that measures only serum or plasma, or a specific measurement of magnesium in red blood cells (intracellular).
Because most of the magnesium in the body is found intracellularly, it is sometimes assumed that a whole-blood magnesium test provides more information about magnesium status than a serum or plasma test alone. However, there is no complete scientific consensus on this assumption.
How are the results interpreted?
The reference ranges for magnesium in whole blood depend on the measurement method used and the laboratory. Unlike serum magnesium, there is no internationally harmonized reference range for whole blood magnesium. Furthermore, the clinical interpretation has not been as extensively validated.
A low value may indicate reduced magnesium status. However, a value within the reference range does not completely rule out a magnesium deficiency.
Important: whole-blood magnesium is not the same as erythrocyte/intracellular magnesium and cannot be considered a direct measure of the body’s total magnesium stores.
Reference Values
The reference ranges used for this test depend on age:
| Age | Reference Value |
|---|---|
| 0–5 months | 0.62–0.91 mmol/L |
| 5 months–6 years | 0.70–0.95 mmol/L |
| Ages 6–12 | 0.70–0.86 mmol/L |
| Ages 12–20 | 0.70–0.91 mmol/L |
| Ages 20–60 | 0.66–1.07 mmol/L |
| 60–90 years | 0.66–0.99 mmol/L |
| 90–120 years | 0.70–0.95 mmol/L |
The results must always be interpreted based on the reference range listed on the laboratory report.
Whole-blood or intracellular magnesium?
A whole-blood magnesium test can be used to assess magnesium status and may be useful, for example, for general screening or for monitoring changes in magnesium levels.
Would you like to specifically examine the amount of magnesium in red blood cells? If so, you can choose the Intracellular Magnesium test. This is a different test and should not be considered the same as the other test.
