The influence of pain-related comorbidities on pain intensity and pain-related psychological distress in patients presenting with musculoskeletal pain.

BACKGROUND: Musculoskeletal pain (MSP) is the largest contributor to chronic pain and frequently occurs alongside other medical comorbidities. OBJECTIVE: Explore the relationships between the presence of pain-related comorbidities, pain intensity, and pain-related psychological distress in patients with MSP. METHODS: A longitudinal assessment of individuals 18-90 years old in the Midwestern United States beginning a new episode of physical therapy for MSP. Electronic medical records were assessed the full year prior for care-seeking of diagnoses for pain-related comorbidities (anxiety, metabolic disorder, chronic pain, depression, nicotine dependence, post-traumatic stress disorder, sleep apnea, and sleep insomnia). Pain intensity and pain-related psychological distress (Optimal Screening for Prediction of Referral and Outcome - Yellow Flags tool) were captured during the physical therapy evaluation. Generalized linear models were used to assess the association between pain intensity, psychological distress, and pain-related co-morbidities. Models were adjusted for variables shown in the literature to influence pain. RESULTS: 532 participants were included in the cohort (56.4% female; median age of 59 years, Interquartile Range [IQR]:47, 69). Comorbid depression (beta coefficient (ß) = 0.7; 95%CI: 0.2, 1.2), spine versus lower extremity pain ((ß = 0.6; 95%CI: 0.1, 1.1), and prior surgery (ß = 0.8, 95%CI: 0.3, 1.4) were associated with higher pain intensity scores. No pain-related comorbidities were associated with pain-related psychological distress (yellow flag count or number of domains). Female sex was associated with less pain-related psychological distress (ß = -0.2, 95%CI: -0.3, -0.02). CONCLUSIONS: Depression was associated with greater pain intensity. No comorbidities were able to account for the extent of pain-related psychological distress.

Incomplete reporting of manual therapy interventions and a lack of clinician and setting diversity in clinical trials for neck pain limits replication and real-world translation. A scoping review.

INTRODUCTION: Neck pain is a leading cause of disability, and manual therapy (MT) is a common intervention used across disciplines and settings to treat it. While there is consistent support for MT in managing neck pain, questions remain about the feasibility of incorporating MT from research into clinical practice. The purpose of this scoping review was to assess the adequacy of MT intervention descriptions and the variability in clinician and setting for MT delivery in trials for neck pain. METHODS: Medline (via PubMed), CINAHL, PEDRo, and the Cochrane Central Registry for Controlled Trials were searched for clinical trials published from January 2010 to November 2021. A 11-item tool modified from the Consensus on Exercise Reporting Template was used to assess appropriateness of intervention reporting. Clinicians, subclassifications of neck pain, and clinical settings were also extracted. RESULTS: 113 trials were included. A low percentage of studies provided the recommended level of detail in the description of how MT was delivered (4.4%), while 39.0% included no description at all. Just over half of trials included clinician's qualifications (58.4%), dose of MT (59.3%), and occurrence of adverse events (55.8%). The proportion of trials with clinicians delivering MT were physical therapists (77.9%), chiropractors (10.6%), and osteopaths (2.7%). DISCUSSION/CONCLUSION: These results reveal incomplete reporting of essential treatment parameters, and a lack of clinician diversity. To foster reproducibility, researchers should report detailed descriptions of MT interventions. Future research should incorporate a variety of MT practitioners to improve generalizability.

Alpha-fetoprotein in pericardial, peritoneal, and pleural fluids: A body fluid matrix evaluation.

OBJECTIVES: Alpha-fetoprotein (AFP) measurement in pericardial, peritoneal (ascites), and pleural fluids is sometimes requested by clinicians as supportive evidence in the evaluation of suspected malignancy. As commercially available, Food and Drug Administration (FDA)-cleared AFP assays are not validated for these fluid types, laboratories must complete additional validation studies to comply with regulatory requirements for body fluid testing. The objective of this study was therefore to conduct a matrix evaluation for these body fluid types using the Beckman Access AFP assay on the UniCel DxI 800 immunoassay system. DESIGN AND METHODS: Using an Institutional Review Board (IRB) approved protocol, previously collected pericardial fluid, peritoneal fluid, pleural fluid, and serum specimens were de-identified and frozen at -20 °C prior to matrix evaluation experiments. Spiked recovery, mixed recovery/linearity, and precision studies were conducted. RESULTS: In spiked and mixed recovery studies, the average percent (%) recovery was within predefined acceptable limits (±15%) for all three body fluids. Linearity was observed over the analytical measurement range (AMR) for all three body fluids (slope, intercept, systematic error): pericardial 0.988, -0.1, 6.1%; peritoneal 0.986, 0.0, 4.1%; and pleural 1.016, 0.0, 1.6%. Imprecision was ≤6.0% CV for all three body fluids at both high and low AFP concentrations. CONCLUSIONS: Matrix interference with AFP testing was not observed for pericardial, peritoneal, or pleural fluids on the Beckman UniCel DxI 800 system.

Performance characteristics of the ARCHITECT Active-B12 (Holotranscobalamin) assay.

BACKGROUND: Vitamin B12 (cobalamin) is a necessary cofactor in methionine and succinyl-CoA metabolism. Studies estimate the deficiency prevalence as high as 30% in the elderly population. Ten to thirty percent of circulating cobalamin is bound to transcobalamin (holotranscobalamin, holoTC) which can readily enter cells and is therefore considered the bioactive form. The objective of our study was to evaluate the analytical performance of a high-throughput, automated holoTC assay (ARCHITECT i2000(SR) Active-B12 (Holotranscobalamin)) and compare it to other available methods. METHODS: Manufacturer-specified limits of blank (LoB), detection (LoD), and quantitation (LoQ), imprecision, interference, and linearity were evaluated for the ARCHITECT HoloTC assay. Residual de-identified serum samples were used to compare the ARCHITECT HoloTC assay with the automated AxSYM Active-B12 (Holotranscobalamin) assay (Abbott Diagnostics) and the manual Active-B12 (Holotranscobalamin) Enzyme Immunoassay (EIA) (Axis-Shield Diagnostics, Dundee, Scotland, UK). RESULTS: Manufacturer's claims of LoB, LoD, LoQ, imprecision, interference, and linearity to the highest point tested (113.4 pmol/L) were verified for the ARCHITECT HoloTC assay. Method comparison of the ARCHITECT HoloTC to the AxSYM HoloTC produced the following Deming regression statistics: (ARCHITECT(HoloTc)) = 0.941 (AxSYM(HoloTC)) + 1.2 pmol/L, S(y/x) = 6.4, r = 0.947 (n = 98). Comparison to the Active-B12 EIA produced: (ARCHITECT(HoloTC)) = 1.105 (EIA(Active-B12)) - 6.8 pmol/L, S(y/x) = 11.0, r = 0.950 (n = 221). CONCLUSIONS: This assay performed acceptably for LoB, LoD, LoQ, imprecision, interference, linearity and method comparison to the predicate device (AxSYM). An additional comparison to a manual Active-B12 EIA method performed similarly, with minor exceptions. This study determined that the ARCHITECT HoloTC assay is suitable for routine clinical use, which provides a high-throughput alternative for automated testing of this emerging marker of cobalamin deficiency.

Body fluid matrix evaluation on a Roche cobas 8000 system.

OBJECTIVES: Chemical analysis of body fluids is commonly requested by physicians. Because most commercial FDA-cleared clinical laboratory assays are not validated by diagnostic manufacturers for "non-serum" and "non-plasma" specimens, laboratories may need to complete additional validation studies to comply with regulatory requirements regarding body fluid testing. The objective of this report is to perform recovery studies to evaluate potential body fluid matrix interferences for commonly requested chemistry analytes. DESIGN AND METHODS: Using an IRB-approved protocol, previously collected clinical body fluid specimens (biliary/hepatic, cerebrospinal, dialysate, drain, pancreatic, pericardial, peritoneal, pleural, synovial, and vitreous) were de-identified and frozen (-20°C) until experiments were performed. Recovery studies (spiking with high concentration serum, control, and/or calibrator) were conducted using 10% spiking solution by volume; n=5 specimens per analyte/body fluid investigated. Specimens were tested on a Roche cobas 8000 system (c502, c702, e602, and ISE modules). RESULTS: In all 80 analyte/body fluid combinations investigated (including amylase, total bilirubin, urea nitrogen, carbohydrate antigen 19-9, carcinoembryonic antigen, cholesterol, chloride, creatinine, glucose, potassium, lactate dehydrogenase, lipase, rheumatoid factor, sodium, total protein, triglycerides, and uric acid), the average percent recovery was within predefined acceptable limits (less than ±10% from the calculated ideal recovery). CONCLUSIONS: The present study provides evidence against the presence of any systematic matrix interference in the analyte/body fluid combinations investigated on the Roche cobas 8000 system. Such findings support the utility of ongoing body fluid validation initiatives conducted to maintain compliance with regulatory requirements.

Liver function testing on the Abaxis Piccolo Xpress: Use in Ebola virus disease protocols.

BACKGROUND: Laboratories that choose a point-of-care approach for liver function testing in patients undergoing evaluation for Ebola virus disease (EVD) have few options to choose from. The primary objective of this study was to conduct a performance characterization of a Clinical Laboratory Improvement Amendments (CLIA)-waived liver function panel on the Abaxis Piccolo® Xpress chemistry analyzer. The secondary objectives were to evaluate multiple specimen types, characterize whole blood specimen stability, and validate disposable exact transfer pipettes. Our final objective was to assess instrument airflow from a biosafety perspective. METHODS: An instrument performance characterization, including precision, linearity, accuracy, reference interval verification, and specimen type evaluation was conducted using Liver Panel Plus reagent discs on the Piccolo® Xpress. RESULTS: All assays demonstrated acceptable linearity (slopes, 0.938-1.061; observed error, 0.8-6.3%). Assay precision was 0.0-3.6% (%CV; within-day studies) and 0.9-5.6% (between-day studies). Method comparison experiments (versus Roche cobas c502/c702 chemistry analyzers) showed excellent correlation for most assays, although a few notable differences were observed (Piccolo versus Roche): alkaline phosphatase, -18.6%; amylase, -29.0%; total bilirubin, +0.3mg/dl. Pre-programmed reference intervals were verified except for the alkaline phosphatase (male and female) and alanine aminotransferase (female), which had greater than 10% of results fall below the programmed ranges. Piccolo instrument results were largely consistent across specimen types tested (lithium-heparin whole blood, lithium-heparin plasma, and serum), although some statistical differences were observed for aspartate aminotransferase, gamma glutamyltransferase, and total protein. Whole blood time course studies demonstrated that some analytes (albumin, amylase, and total protein) showed remarkable stability, while others (such as aspartate aminotransferase) showed a slight trend toward decreased activity over time. Exact volume transfer pipettes provided an effective disposable option for disc loading. Finally, airflow studies suggested that, in the context of EVD protocols, instrument placement in a biosafety level (BSL) 2 cabinet or greater is justified. CONCLUSIONS: Given its analytical performance and ease of operation, the Piccolo Xpress was transferred to a BSL-2 cabinet in our BSL-3 suite for use in our hospital's diagnostic protocol for providing liver function testing in patients undergoing evaluation for EVD.

Multisite evaluation of a monoclonal IMMULITE erythropoietin immunoassay.

BACKGROUND: Erythropoietin (EPO) measurements are useful in diagnosing anemias and polycythemias. We conducted a multisite evaluation of a monoclonal IMMULITE® EPO immunoassay.(1) DESIGN AND METHODS: The IMMULITE EPO assay is a solid-phase enzyme-labeled chemiluminescent immunometric assay. Method comparison to the Beckman ACCESS 2 assay using clinically characterized samples and reproducibility studies were conducted at three external independent laboratories. Internal evaluation conducted at Siemens included comparison of IMMULITE® 2000 and IMMULITE® 1000 assays to the ACCESS 2 assay; imprecision; linearity; limit of blank (LoB), limit of detection (LoD), and functional sensitivity; potential interference and cross-reactants; and reference interval determination. RESULTS: External method comparison gave Deming regression of (IMMULITE 2000)=0.96(ACCESS 2)+2.57IU/L, r=0.98 (n=217). Reproducibility ranged from 6.1% to 16.2%. Internal method comparisons gave Deming regressions of (IMMULITE 2000)=1.09(ACCESS 2)-3.51IU/L, r=0.98 and (IMMULITE 1000)=0.95(ACCESS 2)+0.52IU/L, r=0.95. Total imprecision ranged from 6.4% to 10.3% and linearity was confirmed from 3.5 to 562IU/L. LoB, LoD, and functional sensitivity were 0.5, 1.0, and 1.5IU/L, respectively. The assay was highly specific for EPO. Nonparametric reference interval was 4.3 to 29.0IU/L (n=170). CONCLUSIONS: The monoclonal IMMULITE EPO assay showed acceptable performance for EPO measurement.

Functional sensitivity of seven automated thyroid stimulating hormone immunoassays.

BACKGROUND: Serum thyroid stimulating hormone (TSH) measurements are useful for detecting clinical and subclinical primary hypo- and hyperthyroidism in ambulatory patients. For diagnosis of hyperthyroidism, the functional sensitivity (FS) is an important performance criterion, and current guidelines recommend an FS of ≤0.02 m IU/l for "third" generation performance. METHODS: We evaluated TSH FS for the Access 2, Advia Centaur, Architect i2000, Dimension ExL Modular Analytics E170, Immulite 2000 and Dimension Vista 1500 automated immunoassays using serum pools tested over a 6 week period using 2 reagent lots and 2 calibrations. FS was determined by fitting a power function to the imprecision data using KaleidaGraph software. RESULTS: The FS (m IU/l) for Access 2, ADVIA Centaur, ARCHITECT i2000, Dimension ExL, Modular Analytics E170, Immulite 2000, and Dimension Vista 1500 systems were determined to be 0.039, 0.006, 0.007, 0.003, 0.008, 0.003, and 0.003, respectively. The lowest and next to lowest pools had overall mean TSH concentrations of 0.012 m IU/l and 0.020 m IU/l, respectively and a range of concentrations of 0.005 to 0.022 m IU/l and 0.007 to 0.077 m IU/l, respectively. CONCLUSIONS: All assays showed excellent performance in FS consistent with a "third" generation claim except for the Access 2 system. Further harmonization of TSH immunoassays is required, especially at lower concentrations.

Performance characteristics of a new Immulite(®) 2000 system erythropoietin assay.

BACKGROUND: Serum erythropoietin (EPO) measurements are useful for diagnostic evaluations of anemia, polycythemia, and other erythroid disorders. METHODS: We evaluated a new formulation of the chemiluminescent immunoassay for EPO on the Immulite 2000 analyzer (Siemens Healthcare Diagnostics) for limit of blank (LoB), imprecision, linearity, interference, comparison to another commercially available assay, reference interval, and cross-reactivity with 2 recombinant EPO preparations. RESULTS: The LoB was 0.23IU/l. Total imprecision ranged from 4.2 to 12.1%. The assay was linear from 0 to 678IU/l. Hemoglobin caused negative interference at concentrations >17.4g/l. Deming regression from the method comparison study gave a slope of 1.00±0.04, an intercept of 3.9±12.7, and a S(y/x) of 44.9 (r=0.98). The non-parametric reference interval was 3.3 to 23.4IU/l. Epoetin alfa at a1:2000 dilution gave mean results of 541IU/l and 650IU/l for Immulite 2000 and Access 2, respectively. Darbopoetin alfa at a 1:2000 dilution gave mean results of 337IU/l and 579IU/l for the Immulite 2000 and Access 2, respectively, indicating the 2 assays have substantially different cross-reactivities with recombinant EPO preparations. CONCLUSIONS: The new Immulite 2000 EPO assay shows acceptable performance and is suitable for routine clinical use.

Pediatric reference intervals for random urine calcium, phosphorus and total protein.

The aim of this study was to establish age appropriate reference intervals for calcium (Ca), phosphorus (P) and total protein (UTP) in random urine samples. All analytes were measured using the Roche MODULAR P analyzer and normalized to creatinine (Cr). Our study cohort consisted of 674 boys and 728 girls between 7 and 17 years old (y.o.), which allowed us to determine the central 95% reference intervals with 90% confidence intervals by non-parametric analysis partitioned by both gender and 2-year age intervals for each analyte [i.e. boys in age group 7-9 years (7-9 boys); girls in age group 7-9 years (7-9 girls), etc.]. Results for the upper limits of the central 95% reference interval were: for Ca/Cr, 0.27 (16,17 y.o.) to 0.46 mg/mg (7-9 y.o.) for the girls and 0.26 (16,17 y.o.) to 0.43 mg/mg (7-9 y.o.) for the boys; for P/Cr, 0.85 (16,17 y.o.) to 1.44 mg/mg (7-9 y.o.) for the girls and 0.87 (16,17 y.o.) to 1.68 mg/mg (7-9 y.o.) for the boys; for UTP/Cr, 0.30 (7-9 y.o.) to 0.34 mg/mg (10-12 y.o.) for the girls and 0.19 (16,17, y.o.) to 0.26 mg/mg (13-15 y.o.) for the boys. Upper reference limits decreased with increasing age, and age was a statistically significant variable for all analytes. Eight separate age- and gender-specific reference intervals are proposed per analyte.

Selected performance characteristics of the Roche Elecsys testosterone II assay on the Modular analytics E 170 analyzer.

BACKGROUND: Serum testosterone measurements have utility in diagnosis of clinical conditions characterized by both increased and decreased testosterone concentrations. Studies have indicated that testosterone immunoassays may give inaccurate results for women and children. We evaluated the performance of a second generation testosterone immunoassay from Roche Diagnostics. METHODS: Testo II performed on a Modular Analytics E 170 analyzer is an automated random access electrochemiluminometric assay. We evaluated limit of blank (LoB), imprecision, linearity, interference, and method comparison with liquid chromatography-tandem mass spectrometry assay (LC-MS/MS). Method comparison included the current generation Roche testosterone assay (Testo I) and the Access 2 testosterone chemiluminometric assay (Beckman Coulter). Results for men and women were analyzed for analytic concordance. The relative % differences of immunoassay compared to LC-MS/MS results were evaluated. RESULTS: The LoB was 0.07nmol/l. Total imprecision was <6%. The assay was linear from 0.2 to 46.6nmol/l. Negative interference was observed for lipemia at concentrations >22.5g/l. Analytic concordance showed improved specificity for women. Comparison of results to LC-MS/MS indicated comparable performance with other immunoassays for men and improved performance for women, boys, and girls with mean differences of 0.5%, -0.7%, and 24.4%, respectively. CONCLUSIONS: The Roche Testo II assay demonstrated excellent precision. Comparison to 2 other automated immunoassays showed comparable performance for men and improved performance for women and children. However, challenges still exist for quantifying testosterone concentrations <10.4nmol/l for men and <1.7nmol/l for women and children by immunoassay.

Proteinuria without albuminuria: urinary protein excretion by a subset of patients with burn injuries.

BACKGROUND: There is disagreement regarding the utility of urinary albumin excretion as a marker for capillary injury in patients with severe burn injuries. We examined protein components in urine specimens from patients with burn injury. METHODS: Detailed analysis was performed for a set of 5 urine specimens selected based on a high ratio of albumin-sized molecules by size-exclusion HPLC (Accumin) versus albumin by immunoassay methods. Specimens were analyzed for total protein, alpha(1)-microglobulin, alpha(1)-acid glycoprotein, cystatin C, and retinol-binding protein. Urine components were analyzed by chromatographic and electrophoretic methods. Major components were identified by mass spectrometry of tryptic peptides. RESULTS: A subset of urine specimens had increased total protein with slight increases in albumin by immunoassay or by polyacrylamide gel electrophoresis. Albumin values by size-exclusion HPLC were more than 10-fold higher. Immunoassays for alpha(1)-microglobulin and alpha(1)-acid glycoprotein yielded concentrations 5-10 fold higher than for albumin. Other major components identified included zinc-alpha(2)-glycoprotein and leucine-rich-alpha(2)-glycoprotein. CONCLUSIONS: A subset of patients with burn injury had increased total urinary protein resulting primarily from increased excretion of proteins such as alpha(1)-microglobulin and alpha(1)-acid glycoprotein with little increase in albumin excretion. The unusual composition of urinary proteins in these patients may relate to decreased filtered load of albumin and increased filtered load of acute phase reactants or to alterations in renal tubular protein processing. Thus, measurement of urinary albumin may have decreased sensitivity for detecting kidney injury in burn patients.

A rapid HPLC method used to establish pediatric reference intervals for vitamins A and E.

BACKGROUND: Serum concentrations of the fat-soluble vitamins A (retinol) and E (tocopherol) are measured to assess deficiency and, in the case of vitamin A, toxicity. We modified our existing HPLC method for analyzing vitamins A and E by using a high throughput analytical column and small diameter tubing to reduce analysis time. The modified HPLC method was used to establish pediatric reference intervals for these vitamins. METHODS: Serum or plasma proteins were precipitated with ethanol. A and E vitamins were extracted into hexane, evaporated under nitrogen, dissolved in absolute ethanol, and analyzed by HPLC with ultraviolet detection. RESULTS: The modified HPLC method correlated well with the existing method. Data analysis from the reference interval study resulted in age-dependent intervals for retinol and non-age-dependent intervals for retinyl palmitate, alpha-tocopherol, and gamma-tocopherol. Gender-based reference intervals were not necessary. CONCLUSIONS: We validated a rapid HPLC method for analyzing vitamins A and E that decreased run-time by 60%, mobile phase consumption by 39%, and sample injection volume by 50%. The modified method was used to establish pediatric reference intervals for vitamins A and E in samples from 1136 healthy children aged 7 to 17 y.

Effects of hemoglobin C and S traits on the results of 14 commercial glycated hemoglobin assays.

Glycated hemoglobin is widely used in the management of diabetes mellitus. At least 300,000 Americans with diabetes mellitus have the hemoglobin (Hb) C or S trait. The accuracy of HbA1c methods can be adversely affected by the presence of these traits. We evaluated the effects of HbC and HbS traits on the results of 14 commercial HbA1c methods that use boronate affinity, enzymatic, immunoassay, and ion exchange methods. Whole blood samples from people homozygous for HbA or heterozygous for HbC or HbS were analyzed for HbA1c. Results for each sample type were compared with those from the CLC 330 comparative method (Primus Diagnostics, Kansas City, MO). After correcting for calibration bias by comparing results from the homozygous HbA group, method bias attributable to the presence of HbC or HbS trait was evaluated with a clinically significant difference being more than 10% (ie, 0.6% at 6% HbA1c). One immunoassay method exhibited clinically significant differences owing to the presence of HbC and HbS traits.

Effects of hemoglobin (Hb) E and HbD traits on measurements of glycated Hb (HbA1c) by 23 methods.

BACKGROUND: Glycohemoglobin (GHB), reported as hemoglobin (Hb) A(1c), is a marker of long-term glycemic control in patients with diabetes and is directly related to risk for diabetic complications. HbE and HbD are the second and fourth most common Hb variants worldwide. We investigated the accuracy of HbA(1c) measurement in the presence of HbE and/or HbD traits. METHODS: We evaluated 23 HbA(1c) methods; 9 were immunoassay methods, 10 were ion-exchange HPLC methods, and 4 were capillary electrophoresis, affinity chromatography, or enzymatic methods. An overall test of coincidence of 2 least-squares linear regression lines was performed to determine whether the presence of HbE or HbD traits caused a statistically significant difference from HbAA results relative to the boronate affinity HPLC comparative method. Deming regression analysis was performed to determine whether the presence of these traits produced a clinically significant effect on HbA(1c) results with the use of +/-10% relative bias at 6% and 9% HbA(1c) as evaluation limits. RESULTS: Statistically significant differences were found in more than half of the methods tested. Only 22% and 13% showed clinically significant interference for HbE and HbD traits, respectively. CONCLUSIONS: Some current HbA(1c) methods show clinically significant interferences with samples containing HbE or HbD traits. To avoid reporting of inaccurate results, ion-exchange chromatograms must be carefully examined to identify possible interference from these Hb variants. For some methods, manufacturers' instructions do not provide adequate information for making correct decisions about reporting results.

Development and validation of an automated thawing and mixing workcell.

BACKGROUND: Working toward a goal of total laboratory automation, we are automating manual activities in our highest volume laboratory section. Because half of all specimens arriving in this laboratory section are frozen, we began by developing an automated workcell for thawing frozen specimens and mixing the thawed specimens to remove concentration gradients resulting from freezing and thawing. METHODS: We developed an initial robotic workcell that removed specimens from the transport system's conveyor, blew high-velocity room temperature air at the tubes, mixed them, and replaced them on the conveyor. Aliquots of citrated plasma were frozen with thermocouples immersed in the tubes, and thawing times and temperatures were monitored. Completeness of mixing of thawed specimens was studied by careful removal of small aliquots from the uppermost layer of the upright tubes without disturbing tube contents and analysis of total protein and electrolytes. RESULTS: High velocity ambient air aimed directly at tubes ranging from 12 x 75 to 16 x 100 mm brought specimens to room temperature in a maximum of 23 min. Adequate mixing of the specimens by the workcell's robot required only 2 approximate 126 degrees movements from an upright starting point, a surprising observation, because laboratorians are usually trained to mix 10 or 20 times. We also observed that, in a frozen overfilled tube, resulting analyte concentrations will be lower because more concentrated solutes leak from the tube. CONCLUSIONS: A high-throughput, automated thawing and mixing workcell was successfully built, validated, and installed on our automated transport and sorting system.