Dxi 800 immunoassay system

PSA parameters including total PSA, free PSA, and p2PSA were tested using a Beckman Coulter DxI 800 Immunoassay System (Beckman Coulter, Taiwan Inc.) to obtain PHI (PHI = (p2PSA/free PSA) × √PSA) before prostate biopsy.
Prostate mpMRI examinations were done using a 3-T scanner (Signa HDxt, GE Healthcare, Milwaukee, WI) with a four-channel high definition (HD) cardiac array coil before prostate biopsy or at least 6 weeks after prostate biopsy. The mpMRI protocol included T2-weighted imaging (T2WI), dynamic contrast enhanced (DCE) imaging, diffusion-weighted imaging (DWI) with b values of 0 and 1000–1400 s/mm², and apparent diffusion coefficient (ADC) mapping. All mpMRI scans were interpreted by an experienced radiologist (W. C. L.) who had 12 years of prostate MRI experience with > 500 scans per year, and reported according to PI-RADS version 2 [24 (link)]. The index lesion was defined as the single lesion with the highest PI-RADS score. If there were two or more lesions with the same PI-RADS score, the index lesion was defined as the largest one. We measured the maximal diameter of the index lesion on the axial, coronal, or sagittal view of T2WI to determine the radiological tumor diameter.

We tested PSA parameters including total PSA, free PSA, and p2PSA from serum samples collected before prostate biopsy. After withdrawal of blood, it was centrifuged within 3 h, and frozen at − 20 to − 80 ℃ until analysis [17 (link)]. We used a Beckman Coulter DxI 800 Immunoassay System to determine PHI using the formula PHI = (p2PSA/free PSA) × √PSA [18 (link)].

As a prostate biopsy may lead to PSA elevation, all blood samples were collected before the prostate biopsy. Serum samples were stored at −80 °C, centrifuged at 1500× g for 15 min within three hours of sampling, and stored at −20 °C until analysis. A Beckman Coulter DxI 800 Immunoassay System was used to analyze the tPSA, fPSA, and p2PSA levels. The PHI was calculated according to the following formula: PHI = (p2PSA/fPSA) × (tPSA^1/2) [22 (link)]. The prostate volume was estimated via TRUS by applying the ellipsoid formula: width × length × height × 0.52. PSAD and PHID were calculated with (tPSA/prostate volume) and (PHI/prostate volume), respectively.

Five milliliter of blood samples from pregnant women in their first prenatal examination in the hospital were collected and then were centrifuged to obtain serum. Maternal serum thyroid hormones including TSH, FT3, and FT4 were measured within 24 h by DxI800 Immunoassay System (Beckman CoulterUniCel). The inter-assay coefficients of variation (CVs) at low and high concentrations ranged from 1.88 to 3.92% for FT3, 1.66–2.58% for FT4, and 2.43–2.80% for TSH. The between-assay CVs were 1.60–2.85% for FT3, 1.70–3.30% for FT4, and 2.50–3.80% for TSH. A total of 8,107 pregnant women who had their serum thyroid hormone concentrations within the normal ranges according to the percentile distribution of serum thyroid hormones (TSH, FT3, and FT4 between the 2.5th and 97.5th percentiles) among the whole population. The 2.5th−97.5th percentiles ranges of FT3, FT4 and TSH concentrations were 1.93–3.85 ng/L, 0.55–0.98 ng/dL, and 0.10–3.24 uIU/mL, respectively.

After 12 h of overnight fasting, blood samples were obtained from all participants. The serum was separated and tested immediately. After internal quality control, the serum levels of folate, vitamin B12 and ferritin were measured by the chemiluminescence method (Beckman Coulter, DXI-800-Immunoassay System) in the Clinical Laboratory of Shanxi Provincial People’s Hospital. The accepted normal serum folate level and serum vitamin B12 level was 4.0–18.7 ng/mL and 180–914 ng/L, respectively. Serum ferritin level was used to assess iron status with a normal level of 11.0–306.8 ng/mL for females and 15–336.2 ng/mL for males. Serum vitamin B12, folate and ferritin deficiencies were defined as a serum level below their lower cutoff values, respectively. The hemoglobin (Hb) level was also determined and anemia was diagnosed when the Hb level was lower than the lower cut-off value (male, < 13 g/dL; female, < 12 g/dL).

All patients’ serum samples were collected before performing a TRUS-guided biopsy (TRUS-Bx). The samples were evaluated for specific PSA parameters, including tPSA, fPSA, and p2PSA. Thereafter, the blood samples were centrifuged for three hours and frozen at −20 to −80 ℃ until analysis. We used an immunoassay system (Beckman Coulter DxI 800 Immunoassay System) to determine PHI, which was calculated using the following formula: [16 (link)].