IntroductionCoagulation pathway changes play an important role in the outcome of both clot propagation and fibrinolysis. The structurefunction relationship of the developing fibrin clot is known to be affected by many factors, such as environment, therapy, and disease, compared with normal clot growth. 1,2 A fibrin clot's primary microstructure consists of a disordered network of entangled, branching fibrin fibers. Thinner fibers are associated with networks that display an increased number of branch points, creating denser, less permeable clots that have a known association with thromboembolic disease. [3][4][5][6] More open/permeable networks are formed from thicker fibers, the latter displaying a reduced number of branch points for a given amount of fibrinogen and producing a more porous system. [7][8][9][10] Clots with altered fibrin microstructure exhibit different susceptibility to fibrinolysis, 8,10,11 with clot permeability being the rate-limiting factor for the activity of the fibrin network degradation enzyme plasmin. The permeability will aid or hamper the ability of tissue plasmin activator, tPA, and/or urokinase plasmin activator to move through the 3-dimensional fibrin network and activate the zymogen plasminogen to fibrinolytic plasmin. The effect of anticoagulants such as heparin in the therapeutic manipulation of fibrin clot microstructure by thrombin inhibition increases clot permeability/porosity and produces clots with thicker fibers. 12,13 The evolution of clot microstructure is associated with significant changes in blood viscoelasticity (a measure of a material's viscous and elastic properties). Viscoelastic properties are among the most sensitive measures of fibrin polymerization and blood clot structure. 7,14 In the present study, we focused on the formation of the incipient clot, which provides the microstructural template that determines the future clot morphology, 15-17 by measuring the incipient clot's viscoelastic properties with an oscillatory shear technique known as Fourier transform mechanical spectroscopy (FTMS). [18][19][20] This technique provides an accurate determination of the gel point (GP) of coagulating blood and allows the microstructure of the incipient clot to be quantified by fractal analysis, a technique widely used in medicine and biology to characterize nonlinear growth in branching network structures. 21 The authors of previous studies of clot structure on the basis of techniques such as scanning electron microscopy have reported qualitative descriptions of clot microstructure (involving terms such as "rigid clot structures," "open/porous/dense/loose," etc 1 ), whereas studies of the fractal properties of fibrin gels on the basis of light-scattering techniques have been restricted to dilute solutions of fibrinogen, at concentrations less than those of physiologic relevance in whole blood. 22 A recent study of fibrin clot structure suggests there is a definitive diagnostic potential of characterizing clot structure and the modulation of clot architecture as a pos...

Accurate, reliable laboratory reference ranges are essential for effective clinical evaluation and monitoring. We present robust reference ranges established for haematology, coagulation and haematinic parameters using the Sysmex XE 2100, CA 1500 and Beckman-Coulter Access analysers. Blood samples were taken from 250 healthy laboratory personnel and routine haematology, coagulation and haematinic parameter analysis performed. Our data represent findings from an extensive study to establish reference ranges in healthy adults.

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Establishing clearly defined, accurate reference ranges facilitates good interpretation and effective discrimination between health and disease. These can be used to obviate the need for unnecessary follow-up medical examinations thereby reducing costs. Our data represent findings from one of the most comprehensive studies ever undertaken with the XE-2100 to establish reference ranges (RRs) in healthy adults. Early morning venous samples were collected into Greiner EDTA Vacuettes (Ref: 454286) from 221 healthy laboratory personnel (F= 159;M = 62) aged 20–63 yrs for both gender. Age groups were equally represented. Samples were processed on a Sysmex XE-2100 analyser within 1 hour of collection. NCCLS guidelines (C28-A and H3-A4) were followed throughout. Outliers were excluded, data examined for normal distribution from histograms, Q-Q normality plots, skewness and kurtosis and significance levels calculated from the Kolmogorov-Smirnov and Shapiro-Wilk tests of normality. RRs for near normally distributed parameters were calculated using means ± 2SDs. RRs for non-normally distributed parameters were calculated using the log natural transformation and the antilog of the 2.5- and 97.5- percentiles. Bold parameters shown below have near-normal distribution. Non emboldened values are non-normally distributed. P values are derived from Mann-Whitney U test for differences between males and females. New Limits Historical Limits Test of M&F diff. (P value) *=sig. diff. Haemoglobin (g/dL) M 13.7–17.2 13.0–17.5 <0.05* F 12.0–15.2 11.7–15.7 RBC (x1012/L) M 4.5–5.6 4.5–5.9 <0.05* F 3.9–5.1 3.8–5.9 Hct (L/L) M 0.40–0.50 0.40–0.52 <0.05* F 0.37–0.46 0.37–0.47 MCV (fL) M 83–98 80–100 0.090 F 85–98 80–100 MCH (pg) M 28–33 27–32 0.391 F 28–33 26–31 MCHC (g/dL) M 32–36 30–36 <0.05* F 32–35 30–36 RDW (%) M 11.6–14.1 11.0–15.0 0.067 F 12.0–14.7 11.0–15.0 Reticulocytes (x109/L) M 27–93 25–85 0.138 F 22–76 25–85 Platelets ( (x109/L) M 140–320 140–450 <0.05* F 180–380 140–450 MPV (fL) M 9.4–12.2 6.3–10.1 0.426 F 9.2–12.9 6.3–10.1 Leucocytes (x109/L) 3.6–9.2 4.0–11.0 0.854 Neutrophils (x109/L) 1.7–6.2 2.0–7.5 0.760 Lymphoctes (x109/L) 1.0–3.4 1.0–4.0 0.854 Monocytes(x109/L) 0.2–0.8 0.2–0.8 0.073 Eosinophils(x109/L) 0.00–0.4 0.04–0.4 0.847 Basophils(x109/L) 0.00–0.1 0.00–0.1 0.279 Reference limits determined for total leucocytes and neutrophils are significantly lower than historical ranges. However, leucocyte counts are at their lowest in the early morning. Our findings are in general agreement with previously published data from more limited trials undertaken in other countries.

Reference ranges (RRs) in coagulation are applicable only to specific analyser and reagent combinations and frequently need to be re-established if any of these are changed. In no other sphere of clinical laboratory practice are RRs more affected by such a wide range of multiple demographic and pre-analytical variables. For most routine clinical laboratories therefore, the collection of multiple, separate RRs is not feasible so a representative group of healthy adults such as laboratory staff frequently constitute the reference population from which these limits are calculated. Early morning venous samples were collected into glass B-D Vacutainers (Ref: 367691) from 221 healthy laboratory personnel (F= 159; M = 62) aged 20–63 yrs for both gender. Age groups were equally represented. Samples were processed on a Sysmex CA-1500 analyser within 1 hour of collection. Appropriate NCCLS guidelines were followed throughout. Reagents employed were - Actin FSL (APTT); Innovin (PT); Dade-Behring reference, calibration and deficient plasmas (factor assays); Dade-Behring kit ref: OWWR15 (ATIII); Chromogenix kit ref: 82209863 (Protein C). Outliers were excluded, data examined for normal distribution from histograms and significance levels calculated from the Anderson - Darling test of normality. RRs for normally distributed parameters were calculated using means ± 2SDs. RRs for non-normally distributed parameters were calculated using the log natural transformation and the antilog of 2.5- and 97.5- percentiles. Italicised parameters shown below are non-normally distributed. Parameter Reference Range Anderson Darling P-Value P-value for normal distribution Mann Whitney U-test (M versus F) *=significant difference PT sec 10.0 – 11.8 <0.005 0.003* APTT sec 24.7 – 31.7 0.006 0.232 TCT sec 13.8 – 17.4 0.035 0.198 Fib g/L Clauss 1.6 – 4.2 0.190 t-test not significant Fib g/L Derived 2.1 – 4.9 0.200 t-test not significant II % 82 – 133 <0.005 0.019* V% 70 – 150 0.021 0.303 VII % 60 – 164 0.008 0.037* X% 75 – 147 0.539 t-test not significant VIII % 48 – 204 <0.005 0.520 IX % 65 – 142 <0.005 0.275 XI % 61 – 142 <0.005 0.394 XII % 59 – 133 0.088 t-test not significant Protein C % 75 – 160 0.036 0.024* ATIII % 86 – 128 0.329 t-test not significant Kruskal Wallis tests on our data indicate that all coagulation factors are positively associated with age except factors IX and XII. Significant differences (p=0.014) in factor VIIIc was found between those of blood group O and non group O. Significant correlation was found between declining APTTs and associated increasing factor VIIIc when measured in individual volunteers.

This study describes a method of measuring the INR on native whole blood capillary samples using Innovin recombinant thromboplastin. Modification of the reagent was necessary to compensate for the nonoptimal level of calcium in the sample/reagent mixture. Ninety-five percent of results obtained by the capillary blood method were no more than 0.42 INR higher or 0.38 INR lower than the venous blood method. The effect of changes in haematocrit was minimal. Significant differences in results were found between the Innovin and Thrombotest capillary blood methods. Provided the reagent was properly stored, there was no reagent drift and satisfactory results were obtained on samples supplied by UKNEQAS (coagulation) from previous trials. The method described is a convenient, simple and accurate method of measuring the INR using native capillary whole blood and Innovin recombinant thromboplastin.

In most countries, pathology services have undergone a seriesofradicalreforms,whichhaveimpactedon,moulded and manipulated the professions and the diverse set of occupational groups on which they rely. Reorganisation policies have placed considerable emphasis on the need for carefully planned change management and have highlightedthesensitivenatureofstakeholderinvolvement inhealthcaredeliveryofwhichlaboratorymedicineisavital part.Approximately70%ofpatientmedicalmanagement decisions are based on scientific data generated within diagnostic laboratories as part of the healthcare pathway. Withinthecontextoforganisations,changepresentsthree major problems, resistance, control, and power. Reform driven changes have led to changes in the work-based tasksandcompetenciesofpathologystaffandonestrategy thathealthcareprovidersemploytoadapttothisdynamic environment is multi-skilling as part of a raft of changes aimed at reducing costs and improving performance, efficiency and competitiveness. This paper identifies the factors,whicharecrucialindirectingthemodelsofchange whichneedtobeadoptedtodeliverthemostcost-effective services tailored to meet the needs of patients and the expectationsofserviceusers.

Introduction: The recommended order of draw for multiple tube collections (NCCLS [CLSI] H3-A5) clearly indicate that citrate tubes for coagulation tests should be taken before any other tubes (except blood cultures) and that a discard tube should be used if specialised coagulation tests are to be performed. This is to avoid the possibility of tissue activation and the theoretical risk of additive carryover on the parameters being measured. Because of the paucity of published evidence, this study was performed to determine the effect of the order of draw and whether the use of a discard tube is really necessary. Methods: Three consecutive early morning venous samples were collected into siliconised glass B–D Vacutainers containing tri-sodium citrate (Ref: 367691) from 116 healthy laboratory personnel (F= 74; M = 42) aged 20–63 yrs. Age groups were equally represented. Samples were processed on a Sysmex CA1500 analyser within 1 hour of collection. Appropriate CLSI guidelines were followed throughout. All parameters were measured using Dade-Behring reagents: Activated partial thromboplastin time (APTT) (Actin FSL), prothrombin time (PT) and derived fibrinogen (DF) (Innovin), thrombin clotting time (TCT) (Thromboclotin) and Clauss fibrinogen (CF) (Bovine thrombin and Owren’s veronal buffer). For each parameter, the data from each of the three samples were analysed for significant differences by one way analysis of variance (ANOVA). Results: Data obtained on measurements of basic coagulation parameters are shown in the table below. SDs are shown in parenthesis. (ns = not significant). Coagulation Parameter Results and Statistical Analysis Parameter First Sample Second Sample Third Sample ANOVA (p) ns=not significant APTT (secs) 28.3 (1.73) 28.3 (1.73) 27.9 (1.64) 0.230 (ns) PT (secs) 10.9 (0.47) 10.9 (0.47) 10.8 (0.45) 0.368 (ns) TCT (secs) 15.8 (1.03) 15.8 (1.02) 15.7 (1.02) 0.740 (ns) DF (g/L −1) 2.44 (0.54) 2.47 (0.55) 2.48 (0.55) 0.866 (ns) CF (g/L −1) 3.03(0.67) 3.04 (0.67) 3.10 (0.67) 0.825 (ns) No statistically significant differences were found between the first, second or third samples for any of the measured parameters. Conclusions: The CLSI recommends an order of draw for evacuated blood collection tubes in order to reduce the possibility of tissue activation in coagulation samples and the theoretical risk of additive carryover on the parameters being measured. Until now, this was based largely on theoretical probability. This comprehensive study demonstrates that the use of a discard tube is probably unnecessary since there is no statistical difference in any of the parameters measured between the first, second or third samples. Although this potentially obviates the expensive use of a discard tube in normal subjects, further work is required to determine whether it is necessary when measuring abnormally prolonged parameters in various pathological states.