National audit of cerebrospinal fluid testing.

BACKGROUND: UK National External Quality Assessment Service (NEQAS) Specialist Advisory Group for EQA of CSF Proteins and Biochemistry was interested in current practice for the biochemical investigation of cerebrospinal fluid (CSF) in the UK. METHODS: A questionnaire was sent to laboratories via regional audit committees and the results collated. RESULTS: Most laboratories were analysing CSF in a satisfactory manner. There was some variation in the reference ranges used for glucose, protein and lactate. There was concern about the rejection policies of some laboratories on these unrepeatable samples and the wavelengths used to measure bilirubin. The survey revealed the lack of spectrophotometric scanning for haem pigments and bilirubin in some hospitals. CONCLUSIONS: The current practice for the measurement of CSF samples in the UK is satisfactory in most laboratories responding to the questionnaire. National agreement on reference ranges for glucose, protein and lactate should be achievable. Those performing spectrophotometric scanning of the CSF were doing so in concordance with the national guidelines. Some hospitals in the UK may not have responded to the questionnaire because they did not offer spectrophotometric scanning.

Clinical observations on the significance of raised cardiac troponin-T in patients with myositis of varying etiologies seen in rheumatology practice.

To study the source and clinical relevance of elevated cardiac troponin-T (cTnT) in patients with inflammatory myositis of varying etiology is the objective of this study. Patients with new-onset myositis of varying etiologies and raised serum cTnT and creatine kinase (CK) were identified. Clinical myocardial disease was ruled out on the basis of history, examination, ECG, and 2D-echocardiography. Along with serial estimation of CK levels, cTnT isoforms specific to myocardium (by electrochemiluminescence immunoassay) were used for serial estimation of cTnT levels. Gel-filtration chromatography was performed to investigate the nature of elevated cTnT in myositis patients compared to that in acute coronary syndrome (ACS). Patients requiring hospitalization due to an indication related to myositis were classified as having severe disease. All patients received conventional management for myositis as indicated in individual cases. Eleven patients (eight women, three men; aged 59-87 years) with polymyositis (five), dermatomyositis (three), statin-induced myopathy (two), and inclusion body myositis (one) were studied. The cTnT in myositis patients was found to be identical to cTnT in ACS. The time kinetics of cTnT was different from CK and their levels did not correlate. While CK normalized with treatment, cTnT levels exhibited prolonged elevation. Nine of the patients with raised cTnT had severe disease despite absence of clinical myocardial disease. Three died. cTnT in sera of patients with inflammatory muscle disease is of cardiac origin. It may identify a subgroup with subclinical myocardial involvement with differential response to treatment compared to skeletal muscle. We feel cTnT is an important laboratory investigation in patients with myositis.