Macroprolactinemia detection is important to avoid unneccessary tests and overtreatment. High prolactin levels require routine screening and clinicians must be aware of macroprolactinemia frequency encountered with the method in use. In this study we aimed to determine the macroprolactinemia rate in our laboratory.
Prolactin results of different patients analysed on two different immunoassay systems within two consecutive years were evaluated. Analyses were performed on Beckman Coulter UniCel® DxI800 and Roche Cobas® e601 immunoassay systems. Samples for macroprolactin analysis were precipitated using polyethylene glycol (PEG) 6000. Post-PEG recovery <40% was defined as positive, 40–60% as gray-zone and >60% as negative for macroprolactin.
For the samples analysed on DxI800 (n=14,958) hyperprolactinemia frequency was 8.1% (n=1208). One of 138 samples submitted for macroprolactin analysis was positive, while three of them were in the gray-zone. For the samples analysed on Cobas® e601 (n=14,040) hyperprolactinemia frequency was 13.9% (n=1954). Eighteen of 238 samples submitted for macroprolactin analysis were positive, while 21 of them were in the gray-zone.
A difference was found between two immunoassay systems used in our laboratory in terms of macroprolactinemia rate. However, inability of simultaneous analyses on both systems, lack of evaluation with gel filtration chromatography, and heterophile antibody blocking tube were the limitations.
Hemoglobinopathies are a common public health problem in Turkey. In the screening of these disorders in population, cation-exchange high performance liquid chromatography (HPLC) is accepted as the gold standard method. In this study, the aim was to assess four different HPLC devices used in hemoglobinopathy screening.
Materials and methods
A total of 58 blood samples were analyzed with four different HPLC methods (Bio-Rad variant II, Agilent 1100, Tosoh G8 and Trinity Ultra2 trademarks).
The comparison study demonstrated a good correlation between the results of each HPLC analyzer and the reference value obtained by averaging all the HbA2 results belonging to the methods tested in the study [ (Tosoh G8 (r=0.988), Bio-Rad variant II (r=0.993), Agilent 1100 (r=0.98) and Trinity Ultra2 (r=0.992) ]. HbA2 determination in the presence of HbE was interfered in both Bio-Rad variant II and Tosoh G8.
The analyzers were found to have compatible HbA2 results but with accompanying different degrees of proportional and systematic biases. HPLC analyzers may be affected by different hemoglobin variants at different HbA2 concentrations, which is an important point to take into consideration during the evaluation of HbA2 results in thalassemia screening.