Serum Zinc Test

serum zinc test

Last Updated December 20th, 2021

How important is zinc to the human body?

Zinc is an essential element needed for the body and it plays an important role in the functioning of enzymes, immune systems, and protein synthesis. It also helps in normal growth and development during pregnancy, childhood, and adolescence. Zinc is also essential for wound healing, DNA generation, immune system functioning, taste perception, and reproductive health.

Since the body does not store zinc in any specific tissue, a daily intake of the mineral is essential for good health. In cases when zinc requirements exceed intake or due to any problems in the absorption of the element, a deficiency can occur. Zinc deficiency can cause a wide range of ailments and is regarded as one of the most common nutrient deficiencies prevalent in the world.

What is a serum zinc test?

The serum zinc test measures the level of zinc in the blood serum. While many other nutrient deficiencies are marked by a clear clinical syndrome, in the case of zinc, there is no such indicator. The signs are related to general growth impairment and immune impairment that does not point specifically to the deficiency of the element.

In some cases, the deficiency is also associated with hair loss, poor wound healing, and dermatitis. Zinc is available in high protein foods like meat, fish and dairy products. It is also found in vegetables and grains but its absorption is prevented by the presence of fiber in these food items. Generally, 20% to 30% of ingested zinc is absorbed in the small intestine while a major part of it is lost through the waste products from the body along with sweat and other bodily secretions.

Diseases like hepatic cirrhosis, ulcerative colitis, Crohn’s disease, cancer, regional enteritis, sprue, intestinal bypass, and neoplastic disease also cause the deficiency of the element.

While the chances of excessive zinc in the system are not a major clinical concern, large quantities consumed within a short period of time can result in acute zinc toxicity. This can result in symptoms like abdominal cramps, nausea, vomiting, diarrhea and stomach irritations. In some cases, the presence of excess zinc can affect copper absorption in the body leading to a condition called hypocupremia.

While serum zinc tests are the most common ones conducted, they are affected by many other factors, including inflammation, fasting or eating, pregnancy, oral contraceptive use, and the diurnal rhythm. The results are also affected by stress, fluctuations after meals and increased levels after fasting.

Why do I need to undergo a serum zinc test?

As mentioned, the deficiency of zinc does not have a specific indicator but it is often related to the various conditions mentioned below.

– Delay in growth
– Impaired wound healing
Skin lesions or a dry, scaling skin
– Altered senses of sight, smell, and taste
– Impaired immune system
– Hair loss or alopecia
– Diarrhea
– Impaired testosterone production
– Seizures
– Heart arrhythmia
– Unexplained weight loss and appetite loss.

The test results help to point out whether zinc supplementation is needed due to a deficiency. It also helps to point out what are the concentrations of the supplement that are required. The serum zinc test can also be done with other elements like copper, iron, and selenium to establish an overall picture of nutritional deficiencies in a patient.

How is a serum zinc test performed?

The test is simple in nature and is performed by collecting a small blood sample from the patient through the process of venipuncture. In this process, a needle is inserted into a vein to draw the required volume of blood. The process involves the following steps.

– An elastic band is tied in the upper arm to make the veins swell with blood, thus making them more visible. The collection site is generally around the elbow region and the healthcare practitioner disinfects the area where the needle will be inserted with alcohol. In some cases, blood may also be collected from the back of the hand.

– A needle is inserted into the vein and the required volume of blood is drawn through it in an attached tube. A slight stinging or burning sensation is felt when the needle is inserted.

– The band around the arm is loosened and the needle is then slowly withdrawn. The pressure is applied to the site through a gauze or a cotton piece to prevent any excessive bleeding. The spot is then covered with a sterile bandage and the sample is sent to the laboratory for testing.

– The entire process is safe and is generally concluded within a few minutes. Since the size of the veins can differ from one person to the other, for some patients multiple punctures may be needed before a suitable vein is found.

– Some patients might feel faint or lightheaded after the collection and may require additional care. Any pain or bruising around the collection site is generally cured within a few days. Chances of infection or excessive bleeding from the site are rare but might happen in some exceptional cases which require special treatment.

Trace elements are generally tested in an ultra-clean laboratory environment with a special filtered air system to prevent any specimen contamination. The collected sample is tested for zinc through the process of atomic absorption spectroscopy.

Hemolysis, a condition in which red blood cell rupture occurs, should be avoided in the collected sample. The red blood cells contain as much as 10 times the amount of zinc than in serum and their rupture can bring about false results.

What is the price for a serum zinc test in India?

The cost of the serum zinc test in India ranges between Rs 1000 to Rs 1500 depending on the location and facilities provided in the testing center.

When will I get the test results?

The test results are generally delivered within 24 to 72 hours depending on the laboratory.

What is the normal range for a serum zinc test?

Age group Normal level
0 to 10 years 0.60-1.20 mcg/mL
Above 11 years 0.66 to 1.10 mcg/mL.
Adults 0.66 to 1.10 mcg/mL.

What do the results mean?

The doctor can interpret the results to establish whether you have a zinc deficiency or not. In case there is a deficiency, supplements can be prescribed or changes in the food habit can be suggested. In some cases, depending on the symptoms, the doctor can also order further tests to determine whether the deficiency is related to any other underlying condition or not.

Do I need to fast for the serum zinc test?

Fasting is not required for the serum zinc test. In some cases, the doctor may advise against the consumption of salt-water fishes before the test as that may affect the results.

What else do I need to know before I appear for a serum zinc test?

The following points will throw further light on the serum zinc test.

– Low serum zinc levels are very common in chronic alcoholics and are noted in most cases of alcoholic liver disease. This is because ethanol consumption decreases the intestinal absorption of zinc.

– In alcoholics, zinc deficiency can lead to various disorders including night blindness, hypogonadism that may contribute to osteoporosis and altered cellular immune functions leading to enhanced infection risks.

– Since zinc is transported through the blood via albumin, albumin concentration is also often checked to interpret the serum zinc results.

– A low zinc level with a low albumin concentration can be a result of an infection and not a zinc deficiency.

– Consumption of steroids and oral contraceptives can reduce circulating concentrations of zinc in the blood. The concentration is also lowered during pregnancy due to the action of various hormones.

– The doctor may advise the patient to stop the consumption of nutritional supplements, vitamins, and minerals a week prior to the test to prevent any interference with the results.

Vegetarians consume legumes and whole grains, which contain phytates that inhibit zinc absorption. Consumption of more leavened grain products can help in the increased consumption of zinc.

Since too much consumption of zinc can lead to toxicity in some cases, the recommended dose for adults older than 19 years is no more than 40 milligrams (mg) of zinc in a day.

Can pregnant women undergo a serum zinc test?

Pregnant women can undergo the test without any restrictions.

Is blood serum zinc test possible for new-born babies?

The test is possible for new-born babies as advised by the doctor.


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