Manganese is an essential trace element being required as a co-factor in several enzymes involved in carbohydrate, cholesterol, oxygen radical and nitrogen metabolism. It is found in the diet in grains, nuts and tea. Deficiency is very rare and blood measurement is usually performed to investigate possible toxicity. Its excretion is via the liver into bile and so in some TPN patients, especially those with obstructive liver disease, blood concentrations can increase resulting in tremor and Parkinson's Disease-like symptoms. Brain abnormalities are also visible on magnetic resonance imaging. Manganese toxicity can also develop in patients with portosystemic shunts that may ultimately warrant chelation treatment.44 Tissue manganese concentrations are elevated in long-term TPN patients19 and this has prompted the American Society of Parenteral and Enteral Nutrition (ASPEN) to update their guidelines to indicate that manganese is not supplemented in cholestatic patients.45 During iron deficiency, manganese absorption is increased and so this should be considered in hypermanganesaemic patients.46,47
We recommend whole blood samples for assessment of manganese status and long-term occupational exposure. For whole blood, where the normal concentrations are about ten-fold higher than in serum, the manganese contamination from metal needles is proportionally less significant and so no special precautions are necessary in sampling.
Whole blood concentrations of manganese are significantly raised during pregnancy and show an average three-fold increase in the neonate.48
Manganese toxicity is a known problem in metal refining and manganese ore production. Respiratory illness and eventually neurological effects are seen after years of heavy exposure. No guidelines for biological monitoring are available.
Recommended Daily Allowance
Adults: Males: 2.3 mg/day, Females: 1.8 mg/day
Hardy G. Manganese in parenteral nutrition: who, when, and why should we supplement? Gastroenterol 2009;137:S29-S35.
Sample Requirements and Reference Ranges for Manganese
|Sample Type||Blood (fasting sample preferred)|
|Container||Lithium heparin (non-gel), or ‘Trace Metal’. EDTA unsuitable (unless trace element free). Lithium heparin gel tubes are unsuitable.|
We recommend all plastic lithium heparin non-gel tubes or Sarstedt 2 mL paediatric lithium heparin tubes.
In parenterally fed patients we recommend a fasting sample or sample collected 8 hours after last feed.
|Minimum volume*||300 µL*|
Adult: 70 - 280 nmol/L49
Pregnancy: 90 - 370 nmol/L (third trimester)50
|Mean turnaround time||3.0 days|
|Method||Inductively coupled plasma mass spectrometry|
|Traceability||Blood: Traceable to reference material produced in accordance with EN ISO 17511:2003 “In vitro diagnostic medical devices. Measurement of quantities in biological samples. Metrological traceability of values assigned to calibrators and control materials” and reference materials with values determined by reference laboratories.|
|Intermediate Precision (CV)||7.1% at 342 nmol/L, 5.8% at 769 nmol/L|
|Measurement Uncertainty, U||271 ± 28 nmol/L, 669 ± 52 nmol/L|
|Analytical Goals (CV)||8%**|
|EQA Schemes||UK NEQAS, Guildford (once per month)|
*Absolute minimum volume; this volume is insufficient to carry out repeat analysis if analysis fails.
** Goal Origin: STEMDRL state-of-the-art