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Debido a que la publicación (1) a la que se refiere el Dr. F. J. Martín Gil (2) se trataba de una editorial es posible que no se hayan podido explicar con suficiente detalle lo referido a ¿Material y Métodos¿.
To the editor: In reply to the letter by Dr. F. J. Martín Gil The publication (1) alluded to by Dr. F. J. Martín Gil (2) was an editorial, and this is why the materials and methods may possibly not have been explained in sufficient detail.
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To the editor: In reply to the letter by Dr. F. J. Martín Gil
The publication (1) alluded to by Dr. F. J. Martín Gil (2) was an editorial, and this is why the materials and methods may possibly not have been explained in sufficient detail.
The study on the figures provided by each PTH measurement was performed as follows: whole blood was drawn from 150 patients on hemodialysis. Tubes were subsequently centrifuged and aliquoted, after which they were all stored at -80ºC. In all centers, aliquots were thawed just before analysis. The time from sample thawing to testing could not therefore have influenced the results obtained.
On the other hand, we can guarantee that differences in results were not due to inadequate unit conversion.
As stated by Dr. Martín Gil, serum for PTH measurement is a delicate, easily degraded sample. This is an important
point to be considered by the laboratory sample reception section.
However, the different levels provided by the different tests are a real fact, and are due to the different antibodies used and the different test calibration. Because of this, a normal value may be converted into a pathological value, and vice versa.
This is why the Spanish Society of Nephrology wanted to call the attention of clinicians to this possibility. Results of this study have been summarized in a small card providing formulas for converting a PTH value obtained by a given procedure to the value that would be obtained by the conventional Nichols test.
The group that performed this study intends to prepare a longer publication on this subject in the near future.
We thank Dr. Martín Gil for his letter, that allowed us for a more detailed explanation about some issues that were possibly not sufficiently clear in the editorial.
The publication (1) alluded to by Dr. F. J. Martín Gil (2) was an editorial, and this is why the materials and methods may possibly not have been explained in sufficient detail.
The study on the figures provided by each PTH measurement was performed as follows: whole blood was drawn from 150 patients on hemodialysis. Tubes were subsequently centrifuged and aliquoted, after which they were all stored at -80ºC. In all centers, aliquots were thawed just before analysis. The time from sample thawing to testing could not therefore have influenced the results obtained.
On the other hand, we can guarantee that differences in results were not due to inadequate unit conversion.
As stated by Dr. Martín Gil, serum for PTH measurement is a delicate, easily degraded sample. This is an important
point to be considered by the laboratory sample reception section.
However, the different levels provided by the different tests are a real fact, and are due to the different antibodies used and the different test calibration. Because of this, a normal value may be converted into a pathological value, and vice versa.
This is why the Spanish Society of Nephrology wanted to call the attention of clinicians to this possibility. Results of this study have been summarized in a small card providing formulas for converting a PTH value obtained by a given procedure to the value that would be obtained by the conventional Nichols test.
The group that performed this study intends to prepare a longer publication on this subject in the near future.
We thank Dr. Martín Gil for his letter, that allowed us for a more detailed explanation about some issues that were possibly not sufficiently clear in the editorial.
Bibliography
[1]
Acerca de la Medida de la PTH. FJ Martin Gil. Nefrologia 2008 ; 28 (4) : Añadir paginas
