Let us assume that the practitioner has identified the symptoms as
part of the magnesium deficiency syndrome and intends to start a test
based on the value of the serum concentration of magnesium.
In the literature, a host of different critical values are mentioned
(0.8 mmol/l Mg [3,4,5],
0.75 mmol/l Mg [6,7,8],
0.7 mmol/l Mg [9,10]),
but most of them without correct statistical foundation.
We derive from the data published by v.Ehrlich in 1997
- the average value for the magnesium deficiency patient
is not less than 0.75 mmol/l Mg, probably a bit higher.
- when the distribution is symmetric, a critical value
of 0.8 mmol/l Mg misses about 10% of affected patients.
The estimation of the mean value for the normomagnesiaemic persons
without clinical symptoms varies about the value of 0.9 mmol/l Mg.
When the distribution for the affected is Gaussian,
a critical value of 0.9 mmol/l Mg misses only 1% of the affected.
v.Ehrlich had diagnosed 366 (9,4%) patients among 3894
in total which had symptoms belonging to a clinically relevant
magnesium deficiency syndrome (MDS) and showed less than
0.8 mmol/l Mg [3,4,5].
When patients with more than only
0,7 mmol/l Mg [9,10]
would be considered as normomagnesiaemic, more than 329
magnesium-deficiency patients would be erroneously declared
In these cases (that cover 90% of the affected patients!)
unfortunately, no magnesium therapy would be started.
0,75 mmol/l Mg [6,7,8]
as critical value, v.Ehrlich still had missed 183 (50%)
of the affected patients.
We conclude that 0,8 mmol/l Mg is the critical value
to be applied, when not more than 10% of the affected
patients shall be missed.
When a therapy is started, it should not be reduced before the
MDS patient reached the value of 0,9 mmol/l Mg.