Wr. Kulpmann et al., IONIZED AND TOTAL MAGNESIUM SERUM CONCENTRATIONS IN RENAL AND HEPATICDISEASES, European journal of clinical chemistry and clinical biochemistry, 34(3), 1996, pp. 257-264
Ionised and total magnesium concentrations were determined in the seru
m of different groups of patients suffering from renal or hepatic dise
ases. Ionised magnesium was measured by Microlyte 6 (KONE, Espoo, Finl
and) and total magnesium by atomic absorption spectrometry. In renal i
nsufficiency ionised and total magnesium concentrations were almost eq
ually increased. In proteinuria with a normal glomerular filtration ra
te, ''pseudohypomagnesaemia'' was observed, i. e. decreased total magn
esium concentration in parallel with a decreased albumin concentration
with no significant change in the concentration of ionised magnesium.
Hypermagnesaemia occurred in liver diseases combined with renal insuf
ficiency, whereas ''pseudohypomagnesaemia'' was most often found in th
e absence of renal failure. Also treatment with an aldosterone antagon
ist was associated with a normal ionised magnesium concentration, but
the total magnesium concentration was decreased; when additional magne
sium was administered, the total magnesium concentration approached a
normal value, while ionised magnesium slightly exceeded reference valu
es. Only during cyclosporin treatment did both ionised and total magne
sium concentrations become lowered. However, the decrease of total mag
nesium exceeded that of ionised magnesium due to concomitant hypoalbum
inaemia with reduction of the protein-bound fraction. It is concluded
that especially low total magnesium concentrations should be investiga
ted by measurement of ionised magnesium to exclude ''pseudohypomagnesa
emia''.