Abnormal gel flotation caused by contrast media during adrenal vein sampling.
BACKGROUND
During adrenal venous sampling (AVS) procedure, radiologists administer a contrast agent via the catheter to visualize the proper catheter position.


METHODS
A patient with primary aldosteronism diagnostic-hypothesis was admitted for AVS. A venogram was performed to confirm the catheter's position with 2mL of Iopamidol 300 mg/mL. Samples were collected with syringe connected to a hydrophilic coated catheter by low-pressure aspiration from each of the four collection sites: inferior vena cava in the suprarenal portion, inferior vena cava in the infrarenal portion, left adrenal vein, and right adrenal vein; then immediately transferred from syringe to tubes with gel separator. All tubes were centrifuged at 1200 x g for 10 minutes.


RESULTS
At the end of centrifugation process, primary blood tubes containing blood from inferior vena cava and left adrenal vein exhibited the standard gel separator barrier, while tubes from right adrenal vein showed abnormal flotation of gel separator. The radiologist confirmed the usage of 2.6 mL instead of 2.0 mL of Iopamidol 300 mg/mL. This iodinated contrast media, with 1.33 g/cm3of density, was used close to the right adrenal vein due to some difficulty to access it.


CONCLUSIONS
The abnormal flotation of gel separator in samples taken from right adrenal vein can be explained by the usage of the iodinated contrast media. We suggest using plain-tubes (without gel separator) for AVS in order to avoid preanalytical nonconformities. Moreover, a blood volume equivalent to twice the catheter extension should be discarded to eliminate residual contrast media before collection of samples for laboratory assays.
Laboratory of Clinical Biochemistry, Department of Life and Reproduction Sciences, University of Verona, Italy.
Gabriel
G
Lima-Oliveira
Laboratory of Clinical Chemistry and Hematology, Academic Hospital of Parma, Parma, Italy.
Giuseppe
G
Lippi
Laboratory of Clinical Biochemistry, Department of Life and Reproduction Sciences, University of Verona, Italy.
Gian Luca
GL
Salvagno
Laboratory of Clinical Biochemistry, Department of Life and Reproduction Sciences, University of Verona, Italy.
Matteo
M
Gelati
Laboratory of Clinical Biochemistry, Department of Life and Reproduction Sciences, University of Verona, Italy.
Antonella
A
Bassi
Vascular Interventional Radiology Unit, Institute of Radiology, University of Verona, Italy.
Alberto
A
Contro
Division of Internal Medicine, Department of Medicine, University of Verona, Italy.
Francesca
F
Pizzolo
Laboratory of Clinical Biochemistry, Department of Life and Reproduction Sciences, University of Verona, Italy.
Gian Cesare
GC
Guidi
D000311:Adrenal Glands / Q000098:blood supply*; D003287:Contrast Media / Q000009:adverse effects*; D004586:Electrophoresis / Q000379:methods; D006801:Humans; D006929:Hyperaldosteronism / Q000097:blood*; D008297:Male; D008875:Middle Aged; D014680:Veins
D003287:Contrast Media
blood specimen collection; contrast media; gels; phlebotomy; preanalytical phase