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Reliability of Enderlein's darkfield analysis of live blood
Michael Teut1, Rainer Lüdtke, Albrecht Warning
1Department of Internal Medicine and Geriatrics, Kliniken Essen-Mitte, Essen, Germany.
Context:
In 1925, the German zoologist Günther Enderlein, PhD, published a concept of microbial life cycles. His observations of live blood using darkfield microscopy revealed structures and phenomena that had not yet been described. Although very little research has been conducted to explain the phenomena Dr. Enderlein observed, the diagnostic test is still used in complementary and alternative medicine.
Objective:
To test the interobserver reliability and test-retest reliability of 2 experienced darkfield specialists who had undergone comparable training in Enderlein blood analysis.
Setting:
Inpatient clinic for internal medicine and geriatrics.
Methods:
Both observers assessed 48 capillary blood samples from 24 patients with diabetes. The observers were mutually blind and assessed their findings according to a specific item randomization list that allowed observers to specify whether Enderlein structures were visible or not.
Results:
The interobserver reliability for the visibility of various structures was kappa = .35 (95% CI: .27-.43), the test-retest reliability was kappa = .44 (95% CI: .36-.53).
Conclusions:
This pilot study indicates that Enderlein darkfield analysis is very difficult to standardize and that the reliability of the diagnostic test is low.
