Performance evaluation of colloidal gold test paper for Legionella pneumophila / 中国生物制品学杂志

@#ObjectiveTo prepare colloidal gold immunochromatographic test paper for rapid detection of Legionella pneumophila(LP)and test its performance to ensure that it meets the national clinical diagnostic standards.MethodsLP colloidal gold immunochromatographic test paper was prepared based on double antibody sandwich ELISA,and tested for the cross reactivity,anti-interference,sensitivity,hook effect,stability and other aspects.ResultsLP colloidal gold immunochromatography test paper showed no cross reaction with 22 common pathogens in respiratory tract such as Moraxella catarrhalis,and was not affected by internal and external interferences in respiratory tract;The minimum detection limit for LP was 2.00 × 105cfu/mL,with good sensitivity and no hook effect;Under the conditions of accelerated aging at 45 ℃,simulated high temperature transportation and frozen transportation,the repeatability and stability of test paper were not affected,and the stability was good in the same batch and between different batches.ConclusionThe prepared LP colloidal gold immunochromatographic test paper realized rapid detection of LP,which was simple to operate and had good application prospect and popularization value.

Performance evaluation of the hook effect of five immunoturbidimetric kits for the detection of specific proteins / 国际检验医学杂志

Objective To evaluate the performance of hook effect of five immunoturbidimetric kits for the detection of specific proteins on biochemical analyzers.Methods Five immunoturbidimetric kits with higher market share that came from Beijing BSBE (A), Sichuan maccura (B), Shenzhen Mindray (C), Ningbo Medical System (D) and Beijing Leadman (E) were used to determine six specific proteins.A series of concentration gradient samples were prepared and tested to compare the performance of hook effect from different manufactures′kits when the analytical measurement ranges were known.Results In the five kits, the upper limits of the safe range of antigen excess about ASO, hs-CRP andβ2-MG were relatively higher in B and C.No hook effect occurred at the approximate concentration of 10 000IU/mL, 1 000mg/L and 226mg/L respectively.The highest upper limits for CysC were C and E kits, and both were greater than 112mg/L.The upper limits of the safety range for other manufacturers were more than 700mg/L about RBP except for D.The maximum upper limit of mALB was D.Hook effect did not appear at the concentration of 43 560mg/L approximately.Conclusion Different manufactures′immunoturbidimetric kits have different hook effect performance.The laboratories should verify the hook effect performance before using the kits, and select the most suitable kit to prevent hook effect.

Controversial issues in the management of hyperprolactinemia and prolactinomas - An overview by the Neuroendocrinology Department of the Brazilian Society of Endocrinology and Metabolism

ABSTRACT Prolactinomas are the most common pituitary adenomas (approximately 40% of cases), and they represent an important cause of hypogonadism and infertility in both sexes. The magnitude of prolactin (PRL) elevation can be useful in determining the etiology of hyperprolactinemia. Indeed, PRL levels > 250 ng/mL are highly suggestive of the presence of a prolactinoma. In contrast, most patients with stalk dysfunction, drug-induced hyperprolactinemia or systemic diseases present with PRL levels < 100 ng/mL. However, exceptions to these rules are not rare. On the other hand, among patients with macroprolactinomas (MACs), artificially low PRL levels may result from the so-called "hook effect". Patients harboring cystic MACs may also present with a mild PRL elevation. The screening for macroprolactin is mostly indicated for asymptomatic patients and those with apparent idiopathic hyperprolactinemia. Dopamine agonists (DAs) are the treatment of choice for prolactinomas, particularly cabergoline, which is more effective and better tolerated than bromocriptine. After 2 years of successful treatment, DA withdrawal should be considered in all cases of microprolactinomas and in selected cases of MACs. In this publication, the goal of the Neuroendocrinology Department of the Brazilian Society of Endocrinology and Metabolism (SBEM) is to provide a review of the diagnosis and treatment of hyperprolactinemia and prolactinomas, emphasizing controversial issues regarding these topics. This review is based on data published in the literature and the authors' experience.

Multiple Endocrine Neoplasia Type 1 Presenting with an Invasive Giant Prolactinoma / 대한내과학회지

Pituitary tumors occur in 15-50% of patients with multiple endocrine neoplasia of type 1 (MEN1). To the best of our knowledge, no MEN1 case in which the initial lesion was an invasive giant prolactinoma has been reported from Korea. We describe a patient in whom a skull-base tumor involved the sellar and parasellar spaces. A 49 year-old female presented with headache and diplopia. The tumor was ultimately identified as a giant prolactinoma; the serum prolactin concentration increased from 155.6 ng/mL to 3,234.3 ng/mL after cranial irradiation. She was evaluated in terms of incidental hypercalcemia and was found to have parathyroid hyperplasia. Genetic analysis revealed a missense mutation in the MEN1 gene (c.643G>A, p.Val215Met). Two years of treatment with a dopamine agonist reduced, but did not normalize, the serum prolactin concentration. We highlight the aggressive behavior of the giant skull-base tumor, and the diagnostic delay caused by a high-dose hook effect of the MEN1-related prolactinoma.

Challenges and pitfalls in the diagnosis of hyperprolactinemia / Desafios e armadilhas no diagnóstico da hiperprolactinemia

The definition of the etiology of hyperprolactinemia often represents a great challenge and an accurate diagnosis is paramount before treatment. Although prolactin levels > 200-250 ng/mL are highly suggestive of prolactinomas, they can occasionally be found in other conditions. Moreover, as much as 25% of patients with microprolactinomas may present prolactin levels < 100 ng/mL, which are found in most patients with pseudoprolactinomas, drug-induced hyperprolactinemia, or systemic diseases. On the other hand, some conditions may lead to falsely low PRL levels, particularly the so-called hook effect, that is an assay artifact caused by an extremely high level of PRL, and can be confirmed by repeating assay after a 1:100 serum sample dilution. The hook effect must be considered in all patients with large pituitary adenomas and PRL levels within the normal range or only modestly elevated (e.g., < 200 ng/mL). An overlooked hook effect may lead to incorrect diagnosis and unnecessary surgical intervention in patients with prolactinomas. Another important challenge is macroprolactinemia, a common finding that needs to be identified, as it usually requires no treatment. Although most macroprolactinemic patients are asymptomatic, many of them may present galactorrhea or menstrual disorders, as well as neuroradiological abnormalities, due to the concomitance of other diseases. Finally, physicians should be aware that pituitary incidentalomas are found in at least 10% of adult population. Arq Bras Endocrinol Metab. 2014;58(1):9-22.

A definição da etiologia da hiperprolactinemia muitas vezes representa um grande desafio e um diagnóstico preciso é fundamental antes do tratamento. Embora níveis de prolactina > 200-250 ng/mL sejam altamente sugestivos de prolactinomas, ocasionalmente podem ser encontrados em outras condições. Além disso, até 25% dos pacientes com microprolactinomas podem apresentar-se com níveis de prolactina < 100 ng/mL, os quais são evidenciados na maioria dos pacientes com pseudoprolactinomas, hiperprolactinemia induzida por drogas ou doenças sistêmicas. Por outro lado, deve-se atentar às condições que podem levar a valores de prolactina falsamente baixos, particularmente o chamado efeito gancho. Este último é um artefato causado por um nível extremamente elevado de PRL e que pode ser confirmado pela repetição do exame após diluição do soro a 1:100. O efeito gancho deve ser considerado em todo paciente com grandes adenomas hipofisários e níveis de prolactina dentro da faixa normal ou apenas moderadamente elevados (p. ex., < 200 ng/mL). Um efeito gancho não detectado pode levar a diagnóstico incorreto e intervenção cirúrgica desnecessária em pacientes com prolactinomas. Outro desafio importante é a macroprolactinemia, um achado comum que precisa ser identificado visto que geralmente não requer tratamento. Ainda que a maioria dos pacientes seja assintomática devido à concomitância de outras doenças, muitos podem apresentar galactorreia ou distúrbios menstruais, bem como anormalidades neurorradiológicas. Finalmente, os médicos devem estar cientes de que incidentalomas hipofisários são encontrados em pelo menos 10% da população adulta. Arq Bras Endocrinol Metab. 2014;58(1):9-22.

High-Dose Hook Effect in Patients with Macroprolactinoma / 대한내분비학회지

BACKGROUND: Large amounts of antigen may produce false low values on immunoradiometric assays due to the so-called high-dose hook effect. The physicians' awareness of the possibility of the "high-dose hook effect" will prevent preoperative misdiagnosis. The study was designed to identify the frequency and clinical features of patients with pituitary macroadenomas in whom a high-dose PRL hook effect was documented. METHODS: Our retrospective study involved 42 patients with non-functioning pituitary adenomas (tumor diameter >30mm) who underwent transsphenoidal microsurgery from between Jan 1999 to Aug 2004, and 6 patients with non-functioning pituitary adenoma(tumor diameter>30mm) were selected for prospective study from Sep 2003 to Feb 2004. Our retrospective study also involved 13 patients with macroprolactinoma for the comparison of the clinical features. RESULTS: 1) The presence of a high-dose hook effect was retrospectively suggested when the PRL levels increased in 4 out of the 42 patients with non- functioning adenomas(tumor diameter >30mm) after surgery. Post-operative immunohistochemical staining of their pituitary specimens revealed the tumors to be prolactinoma. 2) Prospectively, dilution testing of the specimens obtained before surgery was done in the 6 patients, and one patient presented with a case of the hook effect. The patient's prolactin level was measured at 53.1ng/mL before dilution and this was increased up to 22,600ng/mL upon the 1:1000 dilution. 3) Conclusively, the hook effect was seen in 5 of the 48 patients(10.4%) with non-functioning pituitary adenoma(tumor diameter >30mm) 4) Compared with other 2 patient groups(the macroprolactinoma(N=13) group, and the non-functioning pituitary tumor(N=43) group), the high-dose PRL hook effect is more likely to be observed in male patients with large pituitary tumors. CONCLUSION: In order to avoid the high-dose hook effect, PRL should be assayed at 1:100~1:200 or even higher dilutions of serum from all patients(and especially the male patients) with large pituitary tumors