Trace metal determinations in blood obtained in evacuated collection tubes

Area of Science:

• Analytical Chemistry
• Clinical Chemistry
• Biochemistry

Background:

• Accurate measurement of trace elements like iron, copper, and zinc is crucial for clinical diagnostics.
• Blood collection methods can introduce pre-analytical variables affecting analyte concentrations.
• Evacuated blood collection tubes are widely used but may pose a risk of contamination for certain elements.

Purpose of the Study:

• To compare the accuracy of iron, copper, and zinc measurements in serum or plasma using different blood collection tubes.
• To evaluate the impact of rubber stopper composition on zinc contamination in evacuated tubes.
• To determine the suitability of commercially available evacuated tubes for routine trace element analysis.

Main Methods:

• Atomic absorption spectrophotometry was employed for quantitative analysis.
• Serum or plasma samples were collected in acid-washed glass containers as a control.
• Samples were also collected using various commercially available evacuated tubes, including specially treated ones to minimize zinc contamination.

Main Results:

• Iron and copper levels in samples from evacuated tubes were comparable to those from acid-washed glass containers.
• All evacuated tubes showed higher zinc values compared to acid-washed glassware.
• Samples from specially prepared tubes exhibited a 10% increase in zinc levels compared to the control.

Conclusions:

• Standard evacuated blood collection tubes introduce zinc contamination, affecting accurate determination.
• Specially prepared evacuated tubes may offer limited utility, potentially suitable only for large-scale screening.
• For precise zinc level determination in clinical settings, traditional blood collection methods using acid-washed glassware are recommended.