SUSPUP (serum sodium to urinary sodium to serum potassium to urinary potassium) and SUSPPUP (serum sodium to urinary sodium to (serum potassium)² to urinary potassium) are calculated structure parameters of the renin–angiotensin-aldosterone system (RAAS). They have been developed to support screening for

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or secondary aldosteronism.

Physiological principle

The

steroid hormone A steroid hormone is a steroid that acts as a hormone. Steroid hormones can be grouped into two classes: corticosteroids (typically made in the adrenal cortex, hence ''cortico-'') and sex steroids (typically made in the gonads or placenta). Wit ...

aldosterone Aldosterone is the main mineralocorticoid steroid hormone produced by the zona glomerulosa of the adrenal cortex in the adrenal gland. It is essential for sodium conservation in the kidney, salivary glands, sweat glands, and colon. It plays ...

stimulates the reabsorption of

sodium Sodium is a chemical element; it has Symbol (chemistry), symbol Na (from Neo-Latin ) and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 element, group 1 of the peri ...

and the excretion of

potassium Potassium is a chemical element; it has Symbol (chemistry), symbol K (from Neo-Latin ) and atomic number19. It is a silvery white metal that is soft enough to easily cut with a knife. Potassium metal reacts rapidly with atmospheric oxygen to ...

in the distal tubuli and the collecting tubes of the

kidney In humans, the kidneys are two reddish-brown bean-shaped blood-filtering organ (anatomy), organs that are a multilobar, multipapillary form of mammalian kidneys, usually without signs of external lobulation. They are located on the left and rig ...

s. Calculating SUSPUP and/or SUSPPUP helps to determine the intensity of

mineralocorticoid Mineralocorticoids are a class of corticosteroids, which in turn are a class of steroid hormones. Mineralocorticoids are produced in the adrenal cortex and influence salt and water balances (electrolyte balance and fluid balance). The primary ...

signalling, which may be helpful in the differential diagnosis of

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and hypokalaemia.

Preconditions of testing

Sodium and potassium concentrations have to be determined in

serum Serum may refer to: Biology and pharmacology *Serum (blood), plasma from which the clotting proteins have been removed **Antiserum, blood serum with specific antibodies for passive immunity *Serous fluid, any clear bodily fluid Places *Serum, Ind ...

and spot

urine Urine is a liquid by-product of metabolism in humans and many other animals. In placental mammals, urine flows from the Kidney (vertebrates), kidneys through the ureters to the urinary bladder and exits the urethra through the penile meatus (mal ...

probes that have been obtained simultaneously or within a short time interval between.

Calculation

SUSPUP = \frac

SUSPPUP = \frac

Interpretation

Reference ranges are 3.6–22.6 for SUSPUP and 0.6–5.3 for SUSPPUP. Increased values support the hypothesis of increased mineralocorticoid stimulation of the distal tubules and collecting tubes, i.e. in cases of hyperaldosteronism. While these parameters have a high sensitivity for screening purposes their specificity may be inferior compared to aldosteron-to-renin ratio (ARR) and potassium concentrations Both parameters may also be elevated in syndrome of inappropriate ADH secretion (SIADH), probably reflecting a compensatory mechanism, where the organism tries to maintain serum sodium concentrations by means of increased renin and/or aldosterone secretion.{{cite journal , last1=Knoop , first1=H , last2=Knoop , first2=U , last3=Behr , first3=J , last4=Heyer , first4=CM , last5=Kuert , first5=S , last6=Roggenland , first6=D , last7=Suermann , first7=M , last8=Dietrich , first8=JW , title=Syndrome of inadequate antidiuretic hormone secretion in pulmonary tuberculosis - a therapeutic challenge. , journal=Pneumologie (Stuttgart, Germany) , date=April 2013 , volume=67 , issue=4 , pages=219–22 , doi=10.1055/s-0032-1326101 , pmid=23420227, doi-access=free

References

Adrenal gland disorders Human homeostasis Static endocrine function tests