Lithium Assay Kit (Colorimetric) (ab235613)
Key features and details
- Assay type: Quantitative
- Detection method: Colorimetric
- Platform: Microplate reader
- Sample type: Other biological fluids, Plasma, Serum
- Sensitivity: 100 µM
Overview
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Product name
Lithium Assay Kit (Colorimetric) -
Detection method
Colorimetric -
Sample type
Serum, Plasma, Other biological fluids -
Assay type
Quantitative -
Sensitivity
100 µM -
Species reactivity
Reacts with: Human -
Product overview
Lithium Assay Kit (Colorimetric) (ab235613) is designed for the quantification of lithium levels in biological fluids such as serum and plasma.
The assay uses a lithium-selective bi-chromatic probe that undergoes an absorbance change at two distinct wavelengths upon binding to Li+ (λ1 = 540 nm, λ2 = 630 nm). The ratio of the two optical measurements is used to accurately calculate sample Li+ concentration. The kit also includes a sodium masking reagent to prevent the possibility of interference by supra-physiological levels of serum Na+ (hypernatremia). Endogenous mono-, di-, and trivalent ions do not interfere with the assay.
The assay is quick, is high-throughput adaptable and has a linear range from 0.5 – 10 nmole lithium per well (corresponding to 0.1 – 2 mM serum lithium). The kit can detect lithium concentration as low as 100 µM in human serum.
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Notes
Lithium, the lightest alkali metal element, is a ductile, reactive metal that occurs in nature as the Li+ cation and is found in various mineral compounds. Physiologically, lithium is present only in trace levels and is not considered to be an essential dietary nutrient. However, lithium is routinely used in medicine as psychoactive drug. Lithium acts as a mood stabilized and is considered to be the gold standard first-line treatment for bipolar depression and acute mania. Patients treated with lithium are less likely to require hospitalization or complete suicide than patients treated with other mood stabilizers or antipsychotics. Chemically, lithium is the simplest possible drug - as an element, it is not metabolized by the body and has zero-order renal elimination kinetics. Lithium has a narrow therapeutic/toxic ratio and requires blood level monitoring, both to ensure efficacy and decrease the risk of toxic side-effects. The target serum concentration for lithium maintenance therapy ranges from 0.6-1.2 mM. At serum levels ≥1.5 mM there is a sharp increase in severe adverse effects. Overt, potentially fatal side effects (such as seizures, ataxia and loss of consciousness) are observed at serum levels > 2.5 mM.
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Platform
Microplate reader
Properties
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Storage instructions
Store at -20°C. Please refer to protocols. -
Components 100 tests Lithium Assay Buffer 1 x 25ml Lithium Standard (10 mM) 1 x 500µl Probe Solution 1 x 10ml Sodium-Masking Solution 1 x 1.5ml
Images
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Lithium Standard curve.
Lithium concentration is directly proportional to the ratio of absorbance measured at 540 nm and 630 nm.
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Specificity for detection of lithium (Li+) over other common monovalent, divalent and trivalent ions (each 10 nmole/well).All other cations tested contribute ≤10% interference when normalized to the signal generated by 10 nmole lithium.
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Estimation of lithium in human serum. Normal “off-the-clot” pooled serum (5 µl, undiluted) was spiked with 0.5 mM, 1.0 mM, 1.5 mM and 2.0 mM lithium standard.Mean lithium concentrations detected in the spiked samples were 0.52 mM, 1.03 mM, 1.53 mM and 2.01 mM, respectively (mean spike recovery rates across all spiked concentrations ranged from 100.3 – 105.5%). Potential interference by excessive serum sodium (hypernatremia) was also tested. Normal human serum (5 μl, undiluted) was spiked with an additional 40 mM NaCl to simulate hypernatremic conditions (serum Na+ ≥175 mM). The signal imparted by the additional 40 mM Na was equivalent to that of 0.062 mM lithium (≤10% interference for the typical therapeutic range). Data are mean ± SEM of 3 replicates, assayed according to the kit protocol.