Biologic variation of common hematologic laboratory quantities in the elderly.

Area of Science:

• Clinical Chemistry
• Hematology
• Gerontology

Background:

• Understanding biologic variation is crucial for interpreting laboratory test results.
• Previous studies on biologic variation have primarily focused on younger populations.
• Assessing variation in elderly individuals is important due to potential age-related physiological changes.

Purpose of the Study:

• To estimate analytic, within-subject, and between-subject biologic variations for key hematologic parameters in healthy elderly subjects.
• To derive objective analytic goals for hematologic assays based on estimated biologic variation.
• To determine the significance of changes in serial results and assess the utility of population-based reference values for elderly individuals.

Main Methods:

• Cohorts of 12 healthy elderly males and 12 females were studied.
• Biologic variations were estimated for leukocytes, erythrocytes, hemoglobin, hematocrit, MCV, MCH, MCHC, platelets, and differential counts.
• Assays were performed using an Ortho ELT-800 automated analyzer.

Main Results:

• Within-subject biologic variation in the elderly was comparable to published data for younger subjects, suggesting preserved homeostasis.
• Objective analytic goals were met for most parameters, except for erythrocytes, hematocrit, MCV, MCH, and MCHC.
• Significant individuality was observed for all quantities, rendering conventional population-based reference values of limited clinical utility for screening.

Conclusions:

• Homeostasis appears to be maintained in healthy elderly individuals concerning hematologic parameters.
• Current analytic goals need refinement for certain hematologic assays in the elderly.
• The significant individuality of hematologic parameters in the elderly necessitates personalized reference intervals for effective disease detection.