ZINC, whole blood and red blood cell
B -Zn KL 2636
E -Zn KL 8208
Zinc, an indispensable trace element for humans, is distributed throughout all body fluids, tissues, and organs. A substantial portion of the body’s zinc resides in muscles (approximately 60%) and bones (around 30%), with a smaller fraction found in the liver and skin. Given its absence of storage within the body, zinc must be obtained from dietary sources. Approximately 30% of dietary zinc is absorbed within the intestines. Subsequently, released zinc in the digestive tract is eliminated through feces, while a minor quantity is excreted via the kidneys and skin.
The majority of zinc within the bloodstream is concentrated in red blood cells. In plasma, zinc primarily binds to albumin and α-macroglobulin. The zinc content within plasma accounts for just approximately 0.1% of the total body zinc. As a fundamental element, zinc contributes to the composition of various metalloenzymes, participating across a broad spectrum of metabolic pathways. It also plays a vital role in genetic material regulation and protein synthesis. Zinc’s significance is particularly pronounced in maintaining immune responses. Additionally, in partnership with copper, zinc serves as a structural component of the superoxide dismutase enzyme (Cu-Zn-SOD), thereby holding a key role in cellular antioxidative defense mechanisms.
Assessing zinc concentration within whole blood or red blood cells provides an accurate reflection of zinc levels within the body.
Indications
Monitoring intake or exposure to trace elements. Diagnostics of zinc deficiency.
Sample
B -Zn 5 mL of lithium-heparin blood
E -Zn 10 mL of lithium-heparin blood (3 mL of red blood cell mass, see instructions below)
Mix the sample well. The tube must not contain any clots. Take trace element samples last in order to cleanse the sampling needle of possible trace element residues. If this is the only test requisition, first take one extra tube.
No fasting is needed. No trace element supplements 12 hours before sampling. The result is normalised to whole blood hematocrit (Hct) value (B -PVK, engl. Complete Blood Count, B -CBC). The client should determine the hematocrit prior to shipping the sample and write the result on the test requisition.
The Hct is essential for interpretation of results. Without a measured Hct value, standard Hct is used.
E -Zn sample treatment
➢ centrifuge the whole blood tube
➢ after centrifugation, remove the plasma and white blood cells off the top of the red blood cells
➢ add a 0.9% NaCl solution volume equivalent to the plasma into the tube
➢ mix the sample by turning
➢ centrifuge
➢ remove the wash solution (NaCl) off the top of the red blood cells
➢ mix well before shipping
The measured result is corrected with the E-Hct standard value; 93% for women and 94% for men.
Storage and delivery
Ship at room temperature on sampling day (shipping Mon-Thu). Store frozen over the weekend, ship at room temperature.
Method
ICP-MS, Accredited method (B -Zn)
Reference ranges, calculated
B -Zn women 65 – 107 µmol/L (Hct 0.39)
B -Zn men 68 – 115 µmol/L (Hct 0.42)
The Hct value affects the reference ranges. The same sample can be used to measure Cu, K, Mg, Mn, P and Se.
E -Zn 145 – 244 µmol/L
The reference areas have been calculated from the Mineral Laboratory Milan research database. Outliers that significantly differed from the reference distribution were excluded. A mid-percentile range of 90% has been established based on the refined dataset. The most recent update was in 2017.
Interpretation of results
Given that zinc isn’t stored within the body, the significance of acquiring zinc through dietary sources becomes paramount. Zinc-rich options include animal-derived products as well as plant-based items such as whole grains, seeds, and nuts. In plant-based foods, zinc absorption can be hindered by the presence of phytate, which binds to zinc and curtails its absorption—this is particularly pertinent for those adhering to a vegan diet. The demand for zinc is notably elevated among children, young adults, pregnant women, and those who are breastfeeding.
During puberty, even a mild to moderate deficiency in zinc can lead to growth inhibition, alterations in male genital growth, and dermatological symptoms. Severe zinc deficiency may manifest in malnourished individuals with acute protein scarcity, gastrointestinal ailments, or alcoholism. Common deficiency symptoms encompass hair loss, diarrhea, reduced taste sensation, skin issues, and various behavioral disturbances. The elderly population, due to compromised nutritional intake, can also experience zinc deficiency, which can result in weakened immunity and susceptibility to infections.
Excessive zinc consumption adversely affects copper absorption. Acute zinc poisoning, stemming from a single dose of 200 mg, can lead to a metallic taste in the mouth, dizziness, nausea, and stomach discomfort. Consistent intake of high doses (60 mg per day) can suppress the activity of copper enzymes, while even higher daily doses (150 mg/day) notably disturb copper metabolism and disrupt the immune response. For adults, the recommended daily zinc intake should not surpass 25 mg. Children’s acceptable zinc intake levels are lower compared to adults.
The measurement of zinc and copper levels holds substantial significance in both preventing and treating conditions arising from either a deficiency or an excess of these metals. Maintaining a balanced intake and absorption of zinc and copper contributes to the body’s normal metabolism and overall well-being.
Inquiries
martin.tornudd@milalab.fi
Last update 8.8.2023
