Information on the stability of serum analytes during storage of serum or whole blood samples is often incomplete and sometimes contradictory. Using a widely available analyser (Hitachi 737/Boehringer), we therefore determined the effects of storage time and temperature on the measured concentrations of the following serum analytes: sodium, potassium, calcium, chloride, inorganic phosphate, magnesium, creatinine, urea, uric acid, bilirubin, cholesterol, HDL-and LDL-cholesterol, triacylglycerols, creatine kinase, aspartate aminotransferase, alanine aminotransferase, -glutamyltransferase, alkaline phosphatase, -amylase, lactate dehydrogenase and cholinesterase.When separated serum was stored at + 9 °C for seven days, the mean changes in inorganic phosphate and lactate dehydrogenase exceeded significantly (p < 0.05 or 0.001, respectively) the maximum allowable inaccuracy according to the Guidelines of the German Federal Medical Council; all other quantities were sufficiently stable.In serum at room temperature, inorganic phosphate, uric acid, HDL-cholesterol and triacylglycerols increased continuously, whereas bilirubin, LDL-cholesterol, creatine kinase and aspartate aminotransferase decreased more than the guidelines permit during the storage period (p < 0.05 for aspartate aminotransferase, p < 0.001 for the other analytes mentioned).In whole blood stored for 7 days at + 9 °C, only the following serum analytes satisfied the stability requirements of the guidelines: calcium, urea, cholesterol, HDL-cholesterol, LDL-cholesterol, triacylglycerols, creatine kinase, -glutamyltransferase and cholinesterase. When stored at room temperature, only sodium, uric acid, bilirubin, cholesterol, triacylglycerols, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, -amylase and cholinesterase were still stable after 3 days.The data collected show that all quantities examined are sufficiently stable for four days in separated serum stored at + 9 °C.

An isoelectric focusing procedure for the detection of oligoclonal IgA in cerebrospinal fluid (CSF) samples is presented. CSF IgA bands were found in 69% of patients with various inflammatory neurological diseases, in 22% of patients with other neurological diseases, but in none of the patients with non-neurological diseases. In patients with inflammatory neurological diseases we examined the relationship between an intrathecal synthesis of oligoclonal IgA and an intrathecal IgA synthesis as proved by a formula recently described by Reiber and Felgenhauer: 83% of patients with an intrathecal IgA synthesis according to the formula of Reiber and Felgenhauer also showed CSF IgA bands whereas 59% of patients without an intrathecal IgA synthesis displayed an intrathecal synthesis of oligoclonal IgA. Seventeen percent of patients with inflammatory neurological diseases were characterized by an intrathecal synthesis of oligoclonal IgA but did not show either an intrathecal IgA synthesis or an intrathecal synthesis of oligoclonal IgG, the detection of oligoclonal IgA therefore being the only evidence of an intrathecal humoral immune response in these patients.

We report the performance characteristics of an assay for determination of bone alkaline phosphatase (ALP) activity after immunoadsorption in microplate wells. Between-run imprecision was between 7.1% and 11.2%. The detection limit was 1.0 U/L. Comparisons with an immunoradiometric test for determination of bone ALP mass concentrations yielded the following regression equation: y = 3.11 + 1.33x with y, the bone ALP activity concentration (U/L) (and x, the bone ALP mass concentration microgram/L) (r +=0.974, n = 103). Using sera from patients with liver diseases and sera from patients with secondary hyperparathyroidism yielded a cross-reactivity of 20% for circulating liver ALP (and its membrane-bound isoform). In patients receiving renal transplants, Z-score analysis revealed that after transplantation the increase in bone ALP activity is more pronounced than total ALP activity. In tumor patients, receiver-operating characteristic analysis revealed that bone ALP activity shows the same diagnostic efficacy as total ALP activity in the detection of bone metastases (as assessed by bone scintigraphy). In multiple myeloma patients, suppressed osteoblast activity was well detectable by bone ALP activity determination.

Summary:Bone marrow transplant recipients may carry an increased risk of bone diseases, involving numerous factors that affect bone mineral metabolism. Interleukin-6 is a potent stimulator of bone resorption in vivo. The soluble fraction of interleukin-6 receptor is reported to trigger osteoclast formation by interleukin-6 in vitro.In a cross-sectional study we measured serum bone alkaline phosphatase concentrations and the urinary excretion of pyridinium cross-links in 21 patients after bone marrow transplantation, and investigated the relationship between these values and those for the plasma levels of interleukin-6 and soluble interleukin-6 receptor.Following bone marrow transplantation female -but not male -patients showed higher serum bone alkaline phosphatase values than age-and sex-adjusted controls (p < 0.05). Both female and male patients were characterized by increased urinary excretion values of pyridinium cross-links (p < 0.05). In contrast to a marked increase of interleukin-6 plasma levels (p < 0.001) no significant difference in the soluble interleukin-6 receptor levels was found between patients and apparently healthy persons (p = 0.838). Multiple regression analysis (taking into account different variables of the immunosuppressive regimen applied) revealed the plasma concentration of interleukin-6 as an independent predictor of the urinary excretion of pyridinium cross-links (p < 0.05).In conclusion, in patients following bone marrow transplantation, these findings indicate (a) an increase of bone formation in female -but not in male -patients possibly reflecting primary ovarian failure and (b) an enhancement of bone resorption possibly mediated by circulating interleukin-6.

Bone marrow transplant recipients may be at increased risk of osteoporosis. In a cross-sectional study we therefore measured two biochemical markers of bone turnover, bone alkaline phosphatase and the C-terminal propeptide of type I procollagen, in 22 serum samples from 9 patients before ailogeneic bone marrow transplantation and 85 serum samples from 14 patients after ailogeneic bone marrow transplantation.Following ailogeneic bone marrow transplantation, female (but not male) patients showed elevated serum bone alkaline phosphatase values (p < 0.05). After bone marrow transplantation both female and male patients were characterized by elevated serum concentrations of the C-terminal propeptide (p < 0.01). Both the duration of cyclosporin A therapy (p < 0.05) and the time since transplantation (p < 0.01) were independent predictors of serum bone alkaline phosphatase values, whereas the duration of cyclosporin A therapy was the only independent predictor of C-terminal propeptide serum concentrations (p < 0.01). There was a correlation between bone alkaline phosphatase serum concentrations and C-terminal propeptide values in serum (p < 0.0001).These findings indicate an accelerated bone turnover in patients following bone marrow transplantation due to the stimulation of osteoblasts by cyclosporin A. In addition, oestrogen deficiency after total body irradiation may accelerate bone mass loss in female patients.

The performance characteristics of an immunoradiometric assay for bone alkaline phosphatase mass concentration in human sera are reported.Within-run imprecision (n = 20) was 12.1% (x = 7.8 μ §/\) and 3.6% (x = 22.8 Mg/1), between-day imprecision (n = 8) was 10.1% (X = 20.3 μ£/1) and 2.8% (x = 84.3 μ §/1). There was a linear relationship between the concentrations of the Standards employed and the counts per minute up to 120 μ^Ι. The detection limit was 0.3In 102 apparently healthy persons (51 males and 51 females; r nge of age: 18-56 years) the following reference intervals were established: 3.8-21.3 μg/l (males) and 3.4-15.0 μg/l (females).We compared the values obtained using the immunoassay with those obtained by precipitating of bone alkaline phosphatase with wheat-germ lectin (alkaline phosphatase activity concentration was determined at + 25 °C by the optimized Standard method according to the Recommendations of the German Society for Clinical Chemistry). For the reference individuals the relationship between the results pf the two methods is given by the following regression equation: Bone alkaline phosphatase activity concentration [U/l] = 14.81 + 3.28 X bone alkaline phosphatase mass concentration [jigft] (r = + 0.783). In 89 sera from 32 patients before and after renal transplantation (r nge of bone alkaline phosphatase mass concentration: 2-39 μg/l) comparison between the two methods yielded a linear correlation coefficient of r = + 0.886.Of 20 sera taken from patients suffering from various hepatobiliary diseases (r nge of total alkaline phosphatase activity concentration: 217-3270 U/l) 18 (90%) showed a bone alkaline phosphatase mass concentration above the upper reference limit (r nge of bone alkaline phosphatase mass concentration: 16-206 μg/l). This is probably due to a cross-reactivity of the antibodies employed for the immunoassay of bone alkaline phosphatase with liver alkaline phosphatase in plasma. It is concluded that an increased release of liver alkaline phosphatase into serum leads to falsely high values for bone alkaline phosphatase mass concentration, severely limiting the diagnostic validity of the test in such cases.

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Bone sialoprotein (BS), a protein synthesized by osteoblasts and osteoclasts and highly modified posttranslationally, constitutes a predominant fraction of the noncollagenous organic matrix in human bone. We report an assessment of serum concentrations of BS in patients with malignant bone diseases. In patients with bone metastases (according to scintigraphic criteria), serum BS concentrations were greater than in patients without bone metastases (P &lt;0.05). However, ROC curve analysis revealed that serum BS was inferior to serum bone alkaline phosphatase in discriminating between patients with and without bone metastases. Patients with bone metastases showed a weak correlation between serum BS concentrations and bone formation markers. Only “traditional” markers of bone formation—but not BS—were correlated with urinary deoxypyridinoline (P &lt;0.01). Liver and kidney dysfunction had no significant influence on BS values in these patients (as assessed by analysis of variance; P &gt;0.05). In multiple myeloma patients treated with corticosteroids and bisphosphonates, BS concentrations were lower than in tumor patients without bone metastases (P &lt;0.001), and the correlation between BS concentrations and the number of bisphosphonate courses applied was significant (r = −0.578; P &lt;0.05). In postmenopausal women, serum BS concentrations averaged 142% greater than in premenopausal women. Further studies should be done, therefore, to elucidate whether serum BS is able to predict high bone turnover after menopause.