Differences between lactate concentration of samples from ear lobe and the finger tip

Area of Science:

• Sports Medicine
• Exercise Physiology
• Biochemistry

Background:

• Blood lactate concentrations are commonly measured from capillary samples.
• Ear lobe and finger tip sampling sites are often used interchangeably for blood lactate analysis.
• This interchangeable use assumes equivalence, which may impact athletic training program design.

Purpose of the Study:

• To investigate the validity of using ear lobe and finger tip capillary blood samples interchangeably for lactate measurements.
• To determine if significant differences exist in blood lactate concentrations between these two sampling sites.
• To assess the practical implications for athletic training program planning and evaluation.

Main Methods:

• Twenty-six elite male athletes (rowers, cyclists, runners) underwent graded exercise tests to exhaustion.
• Simultaneous capillary blood samples were collected from the ear lobe and finger tip at rest, submaximal, and post-exhaustion.
• Lactate concentrations were analyzed from paired samples at three distinct physiological states.

Main Results:

• Significant differences (p < 0.001) were observed in blood lactate concentrations between ear lobe and finger tip samples.
• Finger tip samples consistently demonstrated higher lactate values compared to ear lobe samples.
• Method errors for lactate measurements varied: 27% (rest), 16% (submaximal), and 3% (maximal exercise).

Conclusions:

• The assumption of equivalence between ear lobe and finger tip blood lactate measurements is invalid.
• Finger tip sampling provides higher lactate concentrations than ear lobe sampling.
• This discrepancy necessitates careful consideration when interpreting blood lactate data for athletic training.