Copper is reported to be

stable in the sample for 6 days when stored at 2–8°C.

Procedure

Wavelength/filter : 580 nm (Hg 578 nm)/yellow

Temperature : RT

Light path : 1 cm

Pipette into clean dry test tubes labeled as blank (B),

standard (S), and test (T):

Addition

Sequence

B

(mL)

S

(mL)

T

(mL)

Buffer reagent (L1) 0.5 0.5 0.5

Color reagent (L2) 0.5 0.5 0.5

Distilled water 0.05

Copper standard (s) - 0.05

Sample - - 0.05

Mix well and incubate at RT (25°C) for 10 minutes.

Measure the absorbance of the standard (Abs S), and test

sample (Abs T) against the blank, within 30 minutes.

Calculations

 Abs T

Copper in µg/dL = _______ × 200 Abs S

Linearity

This procedure is linear upto 500 µg/dL. If the value

exceeds this limit, dilute the serum with normal saline

(NaCL 0.9%) and repeat the assay. Calculate the value

using the proper dilution factor.

Notes

Chelating agents such as EDTA, oxalate and citrate,

present even in traces, prevent the formation of the color

complex, hence necessary care should be taken during the

assay.

Highly lipemic samples could interfere and should be

cleared by centrifugation or filtration before use.

The assay can be run at 600 nm, however the absorbances

would be approx. 30% lower as compared to 570 nm.

System Parameters

Reaction : End point Interval :

Wavelength : 578 nm Sample

volume

: 0.05 mL

Zero setting :  Reagent

blank

Reagent

volume

: 1.00 mL

Incubation

temperature

: RT Standard : 200 µg/dL

Incubated

time

: 10 minutes Factor :

Contd...

506 Concise Book of Medical Laboratory Technology: Methods and Interpretations Delay time : — React slope : Increasing

Read time : — Linearity : 500 µg/dL

No. of read : — Units : µg/dL

Clinical Relevance

Toxic Level Symptoms

Jaundice, hepatic injury, headache, vomiting, and may

lead to hemolytic shock.

Deficiency Symptoms

Impaired erythrocyte production and survival time and

lowered catabolism by copper-containing enzymes.

Values are Increased in

Alzheimer’s disease, anemia (aplastic, pernicious,

megaloblastic anemia of pregnancy; iron deficiency),

cirrohosis (biliary), elevated CRP, glomerulonephritis,

hemochromatosis, Hodgkin’s disease, hyperestrogenemia,

hypothyroidism, hyperthyroidism, infections, leukemia,

lymphoma, Lofgren syndrome, myocardial infarction,

pellagra, pregnancy (especially third trimester), rheumatic

fever, rheumatoid arthritis, sarcoidosis, and systemic lupus

erythematosus. Drugs include carbamazepine, estrogens and

oral contraceptives, henobarbital, and phenytoin sodium.

Copper Urine

Normal Values

All ages 0–60 µg/24 h

Wilson’s disease > 100 µg/24 h

Values are Increased in

Alzheimer’s disease, aminoaciduria, cirrhosis

(biliary, Indian childhood), hepatitis (chronic active),

hyperceruloplasminemia, nephritic syndrome, pellagra,

proteinuria, and Wilson’s disease.

Values are Decreased in

Burns, hypoproteinemia, Kwashiorkor, malabsorption,

Menkes’ Hair syndrome, nephrosis, and Wilson’s disease.

MAGNESIUM

Oxidation + 2,

Atomic number 12,

Atomic symbol Mg,

Atomic weight 24.305,

Electron configuration—2-8-2.

Calmagite Method

(Courtesy: Tulip Group of Companies)

For the determination of magnesium in serum, urine and

CSF (Laboratory reagent for professional use only).

Summary

Magnesium, along with potassium, is a major intracellular

cation. It is an activator of various enzymes. It is also involved

in amino acid activation and protein synthesis. Increased

levels are found in dehydration, Addison’s disease and

uremia. Decreased levels are found in malabsorption,

during treatment of diabetic coma, chronic renal disease,

chronic alcoholism, pancreatitis and hyperthyroidism.

Principle

Magnesium combines with Calmagite in an alkaline medium

to form a red colored complex. Interference of calcium and

proteins is eliminated by the addition of specific chelating

agents and detergents. Intensity of the color formed is

directly proportional to the amount of magnesium present

in the sample.

 Alkaline

Magnesium + Calmagite Red colored complex

 Medium

Normal Reference Values

Serum (Children) : 1.5–2.0 mEq/L

(Adults) : 1.3–2.5 mEq/L

CSF : 2.0–3.0 mEq/L

Urine : 6.0–8.5 mEq/24 h

It is recommended that each laboratory establish its

own normal range representing its patient population.

Note : 2 mEq/L = 1 mmol/L = 2.44 mg/dL

Contents 25 mL 75 mL

L1: Buffer reagent 12.5 mL 37.5 mL

L2: Color reagent 12.5 mL 37.5 mL

S: Magnesium standard (2.0 mEq/L) 2 mL 2 mL

Storage/Stability

Contents are stable at 2–8°C till the expiry mentioned on

the labels.

Reagent Preparation

Reagents are ready to use. Protect from bright light.

Working reagent: For larger assay series a working reagent

may be prepared by mixing equal volumes of L1 (Buffer

reagent) and L2 (Color reagent). The working reagent is

stable at 2–8°C for at least one month. Keep tightly closed.

Contd...

Clinical Chemistry 507

Sample Material

Serum (Free from hemolysis), urine and CSF.

24 hour collected urine should be acidified to a pH of

2–3 by the addition of approx. 10 to 15 mL of HCI and

diluted 1 + 3 with deionized. Water before use. Multiply

results by 4. Magnesium is reported to be stable in serum/

plasma for 7 days at 2–8°C.

Procedure

Wavelength/filter : 510 nm (Hg 546 nm)/green

Temperature : RT

Light path : 1 cm

Pipette into clean dry test tubes labeled as blank (B),

standard (S), and test (T):

Addition

Sequence

B

(mL)

S

(mL)

T

(mL)

Buffer reagent (L1) 0.5 0.5 0.5

Color reagent (L2) 0.5 0.5 0.5

Distilled water 0.01

Magnesium standard (s) - 0.01

Sample - - 0.01

Mix well and incubate at RT (25°C) for 5 minutes.

Measure the absorbance of the standard (Abs S), and test

sample (Abs T) against the blank, within 30 minutes.

Calculations

 Abs T

Magnesium in mEq/L = _________ × 2 Abs S

Linearity

This procedure is linear upto 10 mEq/L. If values exceed

this limit, dilute the sample with distilled water and

repeat the assay. Calculate the value using an appropriate

dilution factor.

Notes

All glassware being used for the test should first be rinsed

with 1% or 0.1 N HCI and then with good quality deionized

water before use.

Chelating agents such as EDTA, oxalate and citrate,

present even in traces, prevent the formation of the color

complex, hence necessary care should be taken during the

assay.