Pleural homocysteine for malignant pleural effusion: A prospective and double-blind diagnostic test accuracy study

Diagnostic accuracy of pleural fluid complement C1q for tuberculous pleural effusion in elderly patients

BACKGROUND

Previous studies indicated that pleural fluid complement C1q was helpful for diagnosing tuberculous pleural effusion (TPE), but the participants in these studies were young. The diagnostic accuracy of C1q for TPE in elderly patients remains unknown. This study aimed to investigate the diagnostic accuracy of C1q for TPE in elderly patients.

METHODS

We prospectively recruited patients with undiagnosed pleural effusion who visited the Affiliated Hospital of Inner Mongolia Medical University between September 2018 and July 2021. Their C1q in pleural fluid was detected, and the diagnostic accuracy of C1q was assessed by the receiver operating characteristic (ROC) curve analysis.

RESULTS

The median ages of patients with TPE and non-TPE were 75 and 71 years, respectively. TPE patients had significantly higher C1q than non-TPE. The area under the ROC curve (AUC) of C1q was 0.67 (95 %CI: 0.51-0.82). At the threshold of 100 mg/L, C1q had a sensitivity of 0.44 (95 %CI: 0.19-0.69) and specificity of 0.79 (95 %CI: 0.71-0.86).

CONCLUSION

C1q in pleural fluid has low diagnostic accuracy for TPE in elderly patients.

Pleural pro-gastrin releasing peptide is a potential diagnostic marker for malignant pleural effusion induced by small-cell lung cancer

Background

Serum pro-gastrin releasing peptide (proGRP) is a well-recognized diagnostic marker for small cell lung cancer (SCLC). Pleural effusion is common in patients with advanced SCLC. The diagnostic accuracy of pleural proGRP for malignant pleural effusion (MPE) has not yet been established. This study aimed to evaluate the diagnostic accuracy of pleural proGRP for MPE.

Methods

We prospectively recruited patients with undiagnosed pleural effusions from two centers (Hohhot and Changshu). An electrochemiluminescence immunoassay was used to detect pleural fluid proGRP. The diagnostic accuracy of proGRP for MPE was evaluated using a receiver operating characteristic (ROC) curve.

Results

In both the Hohhot (n=153) and Changshu (n=58) cohorts, pleural proGRP in MPE patients did not significantly differ from that in patients with benign pleural effusions (BPEs) (Hohhot, P=0.91; Changshu, P=0.12). In the Hohhot and Changshu cohorts, the areas under the curves (AUCs) of proGRP were 0.51 [95% confidence interval (CI): 0.41-0.60] and 0.62 (95% CI: 0.47-0.77), respectively. However, patients with SCLC-induced MPE had significantly higher proGRP levels than those with BPE and other types of MPE (P=0.001 for both). In the pooled cohort, the AUC of proGRP for SCLC-induced MPE was 0.90 (95% CI: 0.78-1.00, P=0.001). At a threshold of 40 pg/mL, proGRP had a sensitivity of 1.00 (95% CI: 0.61-1.00) and specificity of 0.59 (95% CI: 0.52-0.66). The positive likelihood ratio was 2.61 (95% CI: 1.99-3.41), and the negative likelihood ratio was 0.

Conclusions

Pleural proGRP has no diagnostic value for MPE, but has high diagnostic accuracy for SCLC-induced MPE. In patients with proGRP levels <40 pg/mL, MPE secondary to SCLC can be excluded.

Pleural carbohydrate antigen 50 and malignant pleural effusion: a prospective, double-blind diagnostic accuracy test

Background

Serum carbohydrate antigen 50 (CA50) is an auxiliary diagnostic marker for various solid tumors, but it remains unclear whether CA50 in pleural fluid can assist in the diagnosis of malignant pleural effusion (MPE). This study aimed to evaluate the diagnostic accuracy of pleural fluid CA50 for MPE in pleural effusion patients with undetermined causes.

Methods

This study prospectively recruited pleural effusion patients with undetermined causes who visited the Affiliated Hospital of Inner Mongolia Medical University between September 2018 and July 2021. We measured pleural fluid CA50 level with an electrochemiluminescence assay. We analyzed the diagnostic accuracy of CA50 and carcinoembryonic antigen (CEA) for MPE with the receiver operating characteristic (ROC) curve. The net benefits of CA50 and CEA were analyzed using the decision curve analysis (DCA).

Results

We enrolled 66 MPEs and 87 benign pleural effusions (BPEs). MPE patients had significantly higher CA50 and CEA than BPE patients. The area under the ROC curve (AUC) of CA50 was 0.72 (95% CI: 0.63-0.80). CA50 had a sensitivity of 0.30 (95% CI: 0.19-0.41) and a specificity of 1.00 (95% CI: 1.00-1.00) at the threshold of 15 IU/mL. The decision curve of CA50 was above the reference line at the calculated risk probability of between 0.30 and 1.00. Venn diagram indicated that some patients with low CEA (<50 or <150 ng/mL) and/or negative cytology can be identified by positive CA50 (>15 IU/mL).

Conclusions

Pleural fluid CA50 has moderate accuracy and net benefit for detecting MPE. CA50 >15 IU/mL can be used to diagnose MPE. The combination of CA50 and CEA improves the diagnostic sensitivity for MPE.

A Review of Current Practices and Future Trends in Body Fluid Testing

BACKGROUND

Body fluid testing in the clinical chemistry laboratory is a cornerstone in the diagnostic workup of pathological effusions. Laboratorians may not be aware of the preanalytical workflows used in the collection of body fluids though the value is evident whenever processes change or issues arise. The analytical validation requirements can vary depending on the regulations dictated by the laboratories' jurisdiction and accreditor requirements. Much of analytical validation hinges on how useful testing is to clinical care. Usefulness of testing varies with how well established and incorporated the tests and interpretation are in practice guidelines.

CONTENT

Body fluid collections are depicted and described so clinical laboratorians have a basic appreciation of what specimens are submitted to the laboratory for testing. A review of validation requirements by major laboratory accreditation entities is presented. A review of the usefulness and proposed decision limits for common body fluid chemistry analytes is presented. Body fluid tests that show promise and those that are losing (or lost long ago) value are also reviewed.

SUMMARY

The total testing process from collection to result interpretation can be complicated and easily overlooked by the clinical laboratory. This review aims to improve the understanding and awareness of collections, validation, result interpretation, and provide an update on recent trends.

Age affects the diagnostic accuracy of the cancer ratio for malignant pleural effusion

BACKGROUND AND OBJECTIVE

Cancer ratio (CR), which is defined as serum lactate dehydrogenase (LDH) to pleural fluid adenosine deaminase (ADA) ratio, has been reported to be a useful diagnostic marker for malignant pleural effusion (MPE). Whether its diagnostic accuracy is affected by age remains unknown. This study aimed to investigate the effects of age on the diagnostic accuracy of CR.

METHODS

The participants in this study were from a prospective cohort (SIMPLE cohort, n = 199) and a retrospective cohort (BUFF cohort, n = 158). All participants were patients with undiagnosed pleural effusion (PE). We used receiver operating characteristic (ROC) curves to evaluate the diagnostic accuracy of CR. The effect of age on the diagnostic accuracy of CR was investigated by adjusting the upper limit of age for participant enrolment.

RESULTS

Eighty-eight MPE patients were verified in the SIMPLE cohort, and thirty-five MPE patients were verified in the BUFF cohort. The AUCs of CR in the SIMPLE and BUFF cohorts were 0.60 (95% CI: 0.52-0.68) and 0.63 (95% CI: 0.54-0.71), respectively. In both cohorts, the AUCs of CR decreased with the advancement of age.

CONCLUSION

Age can affect the diagnostic accuracy of CR for MPE. CR has limited diagnostic value in older patients.

KEY MESSAGE

Cancer ratio is a promising diagnostic marker for malignant pleural effusion. This study revealed that its diagnostic accuracy decreased in older patients. Its diagnostic accuracy is overestimated by previous studies using tuberculosis and pneumonia patients as controls.

Value of human epididymis secretory protein 4 in differentiating malignant from benign pleural effusion: an analysis of two cohorts

BACKGROUND

Lung cancer is the most common cause of malignant pleural effusion (MPE). Serum human epididymis secretory protein 4 (HE4) is a useful diagnostic marker for lung cancer.

OBJECTIVE

This study aimed to evaluate the diagnostic accuracy of pleural fluid HE4 for MPE.

DESIGN

A prospective, double-blind diagnostic test accuracy study.

METHODS

Patients with undiagnosed pleural effusion were enrolled in two cohorts (Hohhot and Changshu). Electrochemiluminescence immunoassay was used to detect pleural fluid HE4. The diagnostic accuracy of HE4 was evaluated by a receiver operating characteristic (ROC) curve, and the net benefit of HE4 was assessed by a decision curve analysis (DCA).

RESULTS

A total of 66 MPEs and 86 benign pleural effusions (BPEs) were enrolled in the Hohhot cohort. In the Changshu cohort, 26 MPEs and 32 BPEs were enrolled. In both cohorts, MPEs had significantly higher pleural fluid HE4 than BPEs. The area under the ROC curve (AUC) of HE4 was 0.73 (95% CI: 0.64-0.81) in the Hohhot cohort and 0.79 (95% CI: 0.67-0.91) in the Changshu cohort. At a threshold of 1300 pmol/L, HE4 had sensitivities of 0.44 (95% CI: 0.33-0.56) in the Hohhot cohort and 0.54 (95% CI: 0.35-0.73) in the Changshu cohort. The corresponding specificities were 0.90 (95% CI: 0.83-0.95) in the Hohhot cohort and 0.94 (95% CI: 0.84-1.00) in the Changshu cohort. In subgroup analyses, HE4 had an AUC (95% CI) of 0.78 (0.71-0.85) in exudates and an AUC of 0.69 (0.57-0.81) in patients with negative effusion cytology. The DCA revealed that HE4 determination had a net benefit in both cohorts.

CONCLUSION

Pleural fluid HE4 has moderate diagnostic accuracy for MPE and has net benefit in pleural effusion patients with unknown etiology.