National academy of clinical biochemistry laboratory medicine practice guidelines: follow-up testing for metabolic disease identified by expanded newborn screening using tandem mass spectrometry; executive summary.

BACKGROUND: Almost all newborns in the US are screened at birth for multiple inborn errors of metabolism using tandem mass spectrometry. Screening tests are designed to be sufficiently sensitive so that cases are not missed. The NACB recognized a need for standard guidelines for laboratory confirmation of a positive newborn screen such that all babies would benefit from equal and optimal follow-up by confirmatory testing. METHODS: A committee was formed to review available data pertaining to confirmatory testing. The committee evaluated previously published guidelines, published methodological and clinical studies, clinical case reports, and expert opinion to support optimal confirmatory testing. Grading was based on guidelines adopted from criteria derived from the US Preventive Services Task Force and on the strength of recommendations and the quality of the evidence. Three primary methods of analyte measurement were evaluated for confirmatory testing including measurement of amino acids, organic acids, and carnitine esters. The committee graded the evidence for diagnostic utility of each test for the screened conditions. RESULTS: Ample data and experience were available to make strong recommendations for the practice of analyzing amino acids, organic acids, and acylcarnitines. Likewise, strong recommendations were made for the follow-up test menu for many disorders, particularly those with highest prevalence. Fewer data exist to determine the impact of newborn screening on patient outcomes in all but a few disorders. The guidelines also provide an assessment of developing technology that will fuel a refinement of current practice and ultimate expansion of the diseases detectable by tandem mass spectrometry. CONCLUSIONS: Guidelines are provided for optimal follow-up testing for positive newborn screens using tandem mass spectrometry. The committee regards these tests as reliable and currently optimal for follow-up testing. .

Thyroglobulin: a specific serum marker for the management of thyroid carcinoma.

Thyroglobulin measurements in tissue and serum play an integral role in the evaluation of patients who have thyroid cancer. Immunohistochemical detection of thyroglobulin in surgical specimens is useful in the differential diagnosis of tumors of unknown origin; however, the most important application of thyroglobulin measurement in clinical practice is in the postsurgical management of differentiated thyroid cancer. Serum thyroglobulin is a highly specific and sensitive tumor marker for detecting persistent or recurrent thyroid cancer and for monitoring clinical status. The reappearance of circulating thyroglobulin after total thyroid ablation is pathognomonic for the presence of tumor. The measurement of thyroglobulin in serum is challenging, however, and several analytical problems limit assay performance. Thyroglobulin autoantibody interference is a particularly significant concern that requires all thyroglobulin samples to be screened for their presence. No immunoassay is totally free from interference by thyroglobulin autoantibodies. Measurement of thyroglobulin mRNA to detect circulating tumor cells may help to overcome some of the limitations of current protein-detection methods; serum thyroglobulin will continue to remain the "gold standard." The complex functional features of thyroid carcinomas make sole reliance upon any one diagnostic technique, including thyroglobulin assessments, potentially misleading. Thyroglobulin measurements are a critical component of a multifaceted diagnostic approach to this disease.

Clinical implications of a rising serum CA-125 within the normal range in patients with epithelial ovarian cancer: a preliminary investigation.

OBJECTIVE: The goal of this study was to determine the clinical implications of a progressively rising serum CA-125 level in the normal (< 35 U/ml) range in ovarian cancer patients with complete response to therapy. METHODS: A multi-institutional investigation was undertaken to identify patients with CA-125-producing epithelial ovarian cancers who experienced progressively rising antigen levels in the normal (<35 U/ml) range after completion of therapy. All patients had (1) histologic documentation of epithelial ovarian cancer and (2) complete clinical remission (CR) as defined by negative imaging studies, normal clinical examination, and a normal (<35 U/ml) serum CA-125 value. All patients had serum CA-125 determinations at 1- to 3-month intervals after treatment. A rising serum CA-125 level was defined as a progressive increase in at least three CA-125 values above the coefficient of variation (CV) for the assay. No patient had a known episode of pelvic or gastrointestinal inflammatory disease during the period when the progressive rise in serum CA-125 took place. RESULTS: Eleven patients with rising serum CA-125 levels in the normal range were identified. Original stage of disease was as follows: stage IIA, 1; stage IIIC, 10. Cell type was as follows: endometrioid adenocarcinoma, 4; serous adenocarcinoma, 6; clear cell carcinoma, 1. Of the 11 patients identified, all developed recurrent ovarian cancer. Tumor recurrence was documented either by new lesions appearing on imaging studies (6/11) or by histologic confirmation (5/11). The mean time from CR to recurrence was 21 months (median = 22, range = 12-33). The mean time from the third early rising serum CA 125 value to clinical or radiographic confirmation of recurrence was 189 days (range = 84-518). All recurrences were intraabdominal with the exception of one axillary recurrence. CONCLUSION: In patients with a history of ovarian cancer, three progressively rising serum CA-125 values in the normal range (< 35 U/ml) at 1- to 3-month intervals are associated with a high likelihood of tumor recurrence. Patients with such a pattern should undergo immediate investigation to rule out and/or identify recurrent cancer.