**8. Assessment and diagnosis of the hyperprolactinemia**

224 Prolactin

cannot be dismissed.

concentrations.

(19,20).

b. Macroprolactinemia.

should be precipitated (13, 19-20).

therapy with dopaminergic agonists (13,19-20, 28-30).

limited disorder that can be solved spontaneously (19,31).

if there is indicative clinical symptoms of hyperprolactinemia.

subsequent studies (hormonal and imaging) will be performed only if:


provoke hyperprolactinemia should be assessed, always under psychiatric control.


2. Hyperprolactinemia related to psychotropic drugs

prolactin, this can take to serum values over 2000 ng/ml. It is produced by a decrease of the glomerular filter, although a pituitary primary defect associated to a renal failing

In some patients with hyperprolactinemia without a perceptible cause or idiopathic, this could be due to an excess of macromolecules of prolactin, known as macroprolactin or big prolactin. The macroprolactin is a complex of prolactin joined to an IgG antibody with a low bioactivity but with a higher mean life than normal prolactin, of 23 kDa, which condition its lower clearing and the consequent accumulation of high serum

To distinguish it from other causes, some samples of serum with polyethylene glycol

This prolactin variety can be present in over 10% of the patients with hyperprolactinemia, and its presence should be suspected in every hyperprolactinemia without a defined etiology, with poor or nonexistent symptomatology, despite of the high prolactin serum concentrations and with poor or nonexistent response to normal

This situation can lead to unsuitable diagnosis and treatments in patients with hyperprolactinemia, but usually without clinical significance. Every hyperprolactinemia

When the cause is not found and the imaging tests are negative, the hyperprolactinemia is defined as idiopathic. In most of the cases they are small microadenomas. A 10% of them will be visible between 2 and 6 years. In other cases it is a transitory and self-

Prolactin determinations will not be needed in individual under psychotropic treatment, but

However, in a patient with hyperprolactinemia under psychotropic drugs, among others,

The assessment of the new patient should be done ideally 3 months after the medication suppression or, if not possible, the possibility of a substitutive medication that does not

It is normally not recommended the dopaminergic agonists use in a combined form to psychotropic or dopaminergic antagonist drugs because of the undesirable effects.

assay should consider the possible presence of macroprolactinemia (19, 30).

Because the secretion of the prolactin is pulsatile, it is advisable to determine the serum prolactin in, at least, 2 times or more.

To the most of the clinical laboratories, the normal serum concentration is less than 25 ng/ml in women and 20 ng/ml in men.

(Note: conversion factor: mU/l × 0,0472 =ng/ml; ng/ml × 21,2 = mU/l.)

The determination should be done, ideally, in a basal situation, under rest conditions and after suppression of any medication that can interfere in its quantification.

The clinical records are determinant to the hyperprolactinemia treatment:


Values of serum prolactin can lead to the diagnosis (figure 6):


It is convenient to insist in the importance of differentiate between the big pituitary nonsecretory macroadenomas, that apply compression to the pituitary stalk and can curse with prolactin serum values that are not too high, generally lower than 200 ng/ml (pseudoprolactinoma) from the real macroprolactinomas, which usually show prolactin serum concentrations over 200 ng/ml.

The first ones are susceptible of surgical treatment, while the prolactinomas are treated, most of them, with medical treatment. In a same way, low prolactin serum concentrations can coexist with uncovered small tumors in an incidental way, and they can lead to false diagnosis of microprolactinoma (19, 33).

Nevertheless, values between 20 and 200 ng/ml, in presence of a macro-lesion, obliged to reassess the samples using a dilution of 1:100 to dismiss the hook effect described previously and according to it very high values of serum prolactin saturate the assays and lead to an

apparently low value, that could confuse the macroprolatinoma with a non-secretory macroadenoma (31).

Physiological and Pathological Hyperprolactinemia: Can We Minimize Errors in the Clinical Practice? 227

Our work team has developed a protocol to optimize the samples extraction and the monomeric prolactin measurement, when values are above the reference limits (19). This procedure has shown to reduce the amount of false hyperprolactinemias if compared to the direct puncture technique, because this eliminates the possible increase of prolactin due to

In our protocol (figure 7), patient visit us at 8.00 a.m., following the pre-analitic requirements for prolactin measurement (table 2). Then we place a micro-diffusor (canalizing the vein, which stays permeable, salinizing the blood vessel puncture). Once it has been 60 minutes since the micro-diffuser placement, we will extract the blood sample.

stress puncture.

This image is propriety of our laboratory and created by us.

Be 8-10 hours of fasting prior to extraction.

**Table 2.** Conditions for the extraction of prolactin

Do not be under stress.

**Figure 7.** Protocol of extraction samples to determine the serum prolactin

 Avoid high-protein diet from the day before the extraction Avoid high-fat diet from the day before the extraction. Avoid breast stimulation from the day before the extraction.

 Do not take medications that may increase or decrease prolactin. Be relaxed and rested for at least 30 min before extraction.

Being awake 2 hours before extraction and without making any physical effort.

This image is propriety of our laboratory and created by us.

**Figure 6.** Diagnosis of the hyperprolactinemia

The dynamic tools of suppression or stimulation of prolactin (TRH, L-dopa, etc.) offer inconsistent results and should be rejected (19). In the study of the pituitary gland functionalism, in the case os a microadenoma, the determination of the basal pituitary hormones would be normally enough.

On the other hand, the presence of a macroadenoma would make advisable a deepest anterior hypophysis study.

#### **9. Protocol of samples extraction to determine the serum prolactin**

Prolactin measurement is subjected to a very careful extraction protocol, because most of the errors happen in the pre-analytic stage (between 53-75%) (20, 32).

Due to some physiological stimulus that rise prolactin levels, it is recommended to use 2-3 samples obtained at different times to assure that a patient suffers hyperprolactinemia (19- 20).

Some clinical guides as the "Pituitary Society Guidelines" (35) recommend the macroprolactin screening under certain conditions (moderate increase of prolactin levels and the patient should not show typical symptoms associated to hyperprolactinemia). Other authors recommend the macroprolactin screening performing to all those samples that show high prolactin concentrations (19, 20, 36).

Our work team has developed a protocol to optimize the samples extraction and the monomeric prolactin measurement, when values are above the reference limits (19). This procedure has shown to reduce the amount of false hyperprolactinemias if compared to the direct puncture technique, because this eliminates the possible increase of prolactin due to stress puncture.

In our protocol (figure 7), patient visit us at 8.00 a.m., following the pre-analitic requirements for prolactin measurement (table 2). Then we place a micro-diffusor (canalizing the vein, which stays permeable, salinizing the blood vessel puncture). Once it has been 60 minutes since the micro-diffuser placement, we will extract the blood sample.

This image is propriety of our laboratory and created by us.

**Figure 7.** Protocol of extraction samples to determine the serum prolactin


226 Prolactin

macroadenoma (31).

This image is propriety of our laboratory and created by us. **Figure 6.** Diagnosis of the hyperprolactinemia

hormones would be normally enough.

high prolactin concentrations (19, 20, 36).

anterior hypophysis study.

20).

apparently low value, that could confuse the macroprolatinoma with a non-secretory

The dynamic tools of suppression or stimulation of prolactin (TRH, L-dopa, etc.) offer inconsistent results and should be rejected (19). In the study of the pituitary gland functionalism, in the case os a microadenoma, the determination of the basal pituitary

On the other hand, the presence of a macroadenoma would make advisable a deepest

Prolactin measurement is subjected to a very careful extraction protocol, because most of the

Due to some physiological stimulus that rise prolactin levels, it is recommended to use 2-3 samples obtained at different times to assure that a patient suffers hyperprolactinemia (19-

Some clinical guides as the "Pituitary Society Guidelines" (35) recommend the macroprolactin screening under certain conditions (moderate increase of prolactin levels and the patient should not show typical symptoms associated to hyperprolactinemia). Other authors recommend the macroprolactin screening performing to all those samples that show

**9. Protocol of samples extraction to determine the serum prolactin** 

errors happen in the pre-analytic stage (between 53-75%) (20, 32).

**Table 2.** Conditions for the extraction of prolactin

The monomeric fraction determination was performed when we found high prolactin levels after 60 minutes, then we perform the macroprolactin precipitation through PEG 6000 (20, 36)

Physiological and Pathological Hyperprolactinemia: Can We Minimize Errors in the Clinical Practice? 229

[5] Farreras P.Valenti y Rozman C. Medicina Interna.1982. Décima Edición. Ediciones

[6] Douze H,Guell R,Ventura S,Chueca MP.Comisión de interferencias y efectos de los fármacos. Sociedad Española de Química Clínica. Recomendaciones sobre las interferencias de prolactina en la medición de prolactina. QuimClin. 2006;25:45–8. [7] Benavides IZ, Castillo AP, Montemayor I, DeEstrada R,Onatra W, Posso H. Biorritmo de prolactina en mujeres de edad reproductiva vs.Perimenopáusicas.Rev Coloma

http://www.encolombia.com/medicina/menopausia/Meno9303-Biorritmo1.htm. [8] Hazard J, Perlemuter L. Manual de Endocrinología. Barcelona: Ed. Toray-Masson;

[9] Melmed S, Kleinberg D. Anterior pituitary. In: Kronenberg HM, Melmed S, Polonsky KS, Larsen PR, eds. *Williams Textbook of Endocrinology*. 11th ed. Philadelphia, PA:

[10] Molitch ME. Anterior pituitary. In: Goldman L, Schafer AI, eds. *Cecil Medicine*. 24th ed.

[12] Sapin R,Gasser F,Fischbach E,Grucker D.Détection de la macro-prolactine:une nouvelle

[13] Fuchs, F. y Koppler A. Endocrinología de la Gestación. 1982. Segunda edición. Salvat

[14] Santana F, Fernández GM, Padrón RS. Hiperprolactinemia en el hombre: Estudio de 9

[15] Falaschi P, Frajese G, Sciarra F, et al. Influence of hyperprolactinemia due to

[17] Molitch ME. Disorders of prolactin secretion. Endocrinol Metab Clin North Am 2001:

[18] Moreno B, Obiols G, Páramo C, Zugasti A. Guía clínica del manejo del prolactinoma y

[19] Robles JL, Castaño MA. Empleo de un nuevo protocolo de extracción y disminución de las falsas hiperprolactinemias. Endocrinol Nutr 2010.doi:10.1016/j.endonu.2010.04.004 [20] Kruger TH, Haake P, Chereath D, Knapp W, Janssen OE, Exton MS et al. Specificity of the neuroendocrine response to orgasm during sexual arousal in men. Journal of

[21] Kruger TH, Leeners B, Naegeli E, Schmidlin S, Schedlowski M, Hartmann U et al. Prolactin secretory rhythm in women: immediate and long-term alterations after sexual

[22] Molitch ME. Prolactinomas En: Melmed S, editor. The pituitary, 2nd ed Cambridge:

[23] Schlechte Jk Sherman B, Halmi N, Van Gilde J, Chaplor F, Dolan K, et al. Prolactinsecreting pituitary tumor in amenorrheic women: a comprehensive study. Endocr Rev.

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Polyethylene glycol was mixed in equal parts with the patient serum, then it was stirred and centrifuged. Prolactin was measured in the supernatant (monomeric prolactin).

We show in our report the prolactin measure at 60 minutes, the percentage of recuperation after precipitation with PEG 6000 and the monomeric prolactin (we add in a note this is the fraction that has biological activity).

### **10. Imaging techniques**

Neuro-imaging studies must be performed with any hyperprolactinemia degree that cannot be explained with the purpose of dismiss the hypothalamic-pituitary diseade.

The Magnetic resonance imaging (MRI) with gadolinium gives the most precise anatomical details, and let us measure the tumor size and its relation to the optical chiasma and the cavernosus sinus, that is why this is, nowadays, the best imaging technique (19, 32). If MRI is normal, after excluding other hyperprolactinemia causes, we should talk about idiopathic hyperprolactinemia.

Computed tomography with intravenous contrast is less efficient than MRI in small adenomas diagnosis and the definition of big tumors, but it can be used if MRI cannot be used or if it is contraindicated. The rest of the image techniques that are more usual like X-Rays and isotope techniques are not recommended. (37).

#### **Author details**

Miguel Ángel Castaño López, José Luís Robles Rodríguez and Marta Robles García *Hospital "Juan Ramón Jiménez", Spain* 

#### **11. References**


[5] Farreras P.Valenti y Rozman C. Medicina Interna.1982. Décima Edición. Ediciones Doyma. Capítulo 15 Endocrinología. Páginas 1805, 1806, 1811, 1812, 1814.

228 Prolactin

(20, 36)

fraction that has biological activity).

**10. Imaging techniques** 

hyperprolactinemia.

**Author details** 

**11. References** 

*Hospital "Juan Ramón Jiménez", Spain* 

The monomeric fraction determination was performed when we found high prolactin levels after 60 minutes, then we perform the macroprolactin precipitation through PEG 6000

Polyethylene glycol was mixed in equal parts with the patient serum, then it was stirred and

We show in our report the prolactin measure at 60 minutes, the percentage of recuperation after precipitation with PEG 6000 and the monomeric prolactin (we add in a note this is the

Neuro-imaging studies must be performed with any hyperprolactinemia degree that cannot

The Magnetic resonance imaging (MRI) with gadolinium gives the most precise anatomical details, and let us measure the tumor size and its relation to the optical chiasma and the cavernosus sinus, that is why this is, nowadays, the best imaging technique (19, 32). If MRI is normal, after excluding other hyperprolactinemia causes, we should talk about idiopathic

Computed tomography with intravenous contrast is less efficient than MRI in small adenomas diagnosis and the definition of big tumors, but it can be used if MRI cannot be used or if it is contraindicated. The rest of the image techniques that are more usual like X-

[1] Freeman ME, Kanyicska B, Lerant A, Nagy G. Prolactin:structure, function and

[2] Azíz D.C. Use and Interpretation of Tests in Endocrinology. 1997. Specialty

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[4] Comparato M.R. Terapéutica Hormonal en Ginecología. 1988. Editorial "El Ateneo". Capítulo 2 Hormonas sexuales. Páginas 36-37 Capítulo 13 Terapéutica hormonal en

Miguel Ángel Castaño López, José Luís Robles Rodríguez and Marta Robles García

centrifuged. Prolactin was measured in the supernatant (monomeric prolactin).

be explained with the purpose of dismiss the hypothalamic-pituitary diseade.

Rays and isotope techniques are not recommended. (37).

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Capítulo 37 El puerperio Paginas 818-820.

endocrinología ginecológica Páginas 207-216.

Laboratories. Capítulo 10 Desordenes pituitarios Páginas 129-130

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	- [27] De Shepper J, Schiettecatte J, Velkeniers B, Blumenfeld Z, Shteinberg M, Devroey P, et al. Clinical and biological characterization of macroprolactinemia with and without prolactin-IgG complexes. Eur J Endocrinol 2003;149:201-7.
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	- [30] Lucas T. Problemas en el diagnóstico diferencial de las hiperprolactinemias. Endocrinol Nutr 2004; 51: 241-4.
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	- [37] Casanueva FF, Molitch ME, Sclechte JA, ABS R, Bonert V,Bronstein MD et al. Guías de la Pituitary Society para el diagnóstico y tratamiento de los prolactinomas. Endocrinol Nutr. 2007; 54:438.e1-e10

313-6.

Nutr 2004; 51: 241-4.

Fertil Steril 1987; 48:67-71.

Obstet Gynecol. 1981; 139: 835-44

[24] Schlechte J, Dolan K, Sherma B, Chapler F, Luciano A. The natural history of untreated hyperprolactinemia: a prospective analysis. J Clin Endocrinol Metab. 1989; 68; 412-8. [25] Sisam D, Sheehan JP, Sheehan LR. The natural history of untreated microprolactinomas.

[26] March C, Kletzky O, Davajan V, Teal J, Werss M, Apiuzzo MH et al. Longitudinal evaluation of patients with untreated prolactin-secretingpituitary adenomas. Am J

[27] De Shepper J, Schiettecatte J, Velkeniers B, Blumenfeld Z, Shteinberg M, Devroey P, et al. Clinical and biological characterization of macroprolactinemia with and without

[28] Casamitjana R. Macroprolactinemia: interpretación diagnostic. Endocrinol Nutr 2003;50:

[29] Amadori P, Dilberis C, Marcolla A. All the studies on hyperprolactinemia should not forged the possible presence of macroprolactinemia. Eur J Endocrinol 2004; 150: 93-4. [30] Lucas T. Problemas en el diagnóstico diferencial de las hiperprolactinemias. Endocrinol

[31] Naidich MJ, Russell EJ. Current approaches to imaging of the sellar region and

[32] Torres Y, Acebes JJ, Soler J. Incidentaloma hipofisario: evaluación y abordaje

[33] Cattaneo F, Kappeler D, Müller B. Macroprolactinaemia, the major unknown in the differential diagnosis of hyperprolactinaemia. Swis Med Wkly.2001;131:122–6 [34] Casanueva FF, Molitch ME, Schlechte JA, Abs R, Bonert V, Bronstein MD, et al. Guidelines of the pituitary society for the diagnosis and management of prolactinomas.

[35] Goldschmidt HMJ, Lent RW. Gross errors and work flow analysis in the clinical

[36] Fahie-Wilson M, Bieglmayer C, Kratzsch J, Nusbaumer C, Roth HJ, Zaninotto M, et al. Roche Elecsys Prolactin II assay: reactivity with macroprolactin compared with eight commercial assays for prolactin and determination of monomeric prolactin by pre-

[37] Casanueva FF, Molitch ME, Sclechte JA, ABS R, Bonert V,Bronstein MD et al. Guías de la Pituitary Society para el diagnóstico y tratamiento de los prolactinomas. Endocrinol

prolactin-IgG complexes. Eur J Endocrinol 2003;149:201-7.

pituitary. Endocrinol Metab Clin North Am 1999; 28: 45-79.

terapéutico en la actualidad. Endocrinol Nutr 2003; 50: 153-5.

capitation with polyethyleneglycol. Clin Lab. 2007; 53: 485–92.

Clin Endocrinol (Oxf). 2006; 65: 265–73.

Nutr. 2007; 54:438.e1-e10

laboratory.Clin Biochem Metab.1995; 3: 131–40.
