Reference Intervals of Complete Blood Count and Coagulation Tests in Pregnant Women at Hung Vuong Hospital

Completed

Conditions: Pregnancy Related

Registration Number: NCT05929326

Lead Sponsor: Hung Vuong Hospital

Brief Summary: Rationale: Pregnancy has major effects on physiology in women. There have been many studies that established reference intervals but none was done in Vietnam. The recommendation by CLSI C28-A3 is that if possible, each laboratory establishes its own reference intervals.

Objective: To establish the reference intervals of complete blood count parameters and Prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen.

Study design: This is a cross-sectional study.

Study population: Pregnant women with no history of disease and normal clinical findings.

Detailed Description: Reference intervals (RI) is defined as the central 95% interval of the distribution of values taken from a biological reference population. RI is established for each trimester. The sample needed for each trimester is at least 258 which adds up to 774 when combining three trimesters.

Pregnant women are selected if eligible from obstetrics clinics after history taking and clinical findings. After consent, their blood are then drawn by phlebotomist into an ethylenediamine tetraacetic acid (EDTA) and a trisodium citrate 3.2% blood tube. EDTA samples are run on DxH 900 hematology analyzer, manufactured by Beckman Coulter and citrate samples are run on ACL TOP 550 coagulation analyzer, manufactured by Werfen. The analyzers are verified by laboratory procedure, recommended by Clinical and Laboratory Standards Institute (CLSI) method and quality control is checked before in accordance to the laboratory procedure.

Statistical analysis: Patients were divided into three groups, which are first, second, and third trimester. CLSI EP28-A3c recommended Dixon's D/R ratio outlier test to exclude outliers, where D is the absolute difference between the largest (or smallest) and the second largest (or smallest) observation, and R is the range of all observations. If D is equal to or greater than one-third of R, that observation is considered an outlier and is deleted. After outliers were deleted, the remaining data was tested again for additional outliers until there were no more outliers. A non-parametric method, recommended to establish reference intervals by CLSI EP28-A3c, was used to determine the lower reference limit 2.5th percentile and upper reference limit 97.5th percentile for each group.

Each reference limit was reported along with its 90th confidence interval. Groups were then compared using normal approximation with continuous correction Mann-Whitney U. A two-tailed P-value \< 0.05 was considered significant. Statistical analysis was performed using NCSS statistical software (Utah, USA) version 2023

Recruitment & Eligibility

Status: COMPLETED

Sex: Female

Target Recruitment: 879

Inclusion Criteria

Singleton Pregnancy

Exclusion Criteria

Hypertension, Diabetes, Preeclampsia, Gestational Diabetes, Hemoglobinopathy, Current Infection, Positive Screening for Treponema pallidum, Hepatitis B Virus, HIV, usage of anticoagulant drug.

Study & Design

Study Type: OBSERVATIONAL

Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Trimester Specific Prothrombin Time Reference Interval	Each participant's blood samples are run immediately after phlebotomy within 30 minutes	Prothrombin time in seconds, measured on ACL TOP 550 coagulation analyzer
Trimester Specific Activated Partial Thromboplastin Time Reference Interval	Each participant's blood samples are run immediately after phlebotomy within 30 minutes	Activated partial thromboplastin time in seconds, measured on ACL TOP 550 coagulation analyzer
Trimester Specific Fibrinogen Reference Interval	Each participant's blood samples are run immediately after phlebotomy within 30 minutes	Fibrinogen in milligram/deciLiter (mg/dL), measured on ACL TOP 550 coagulation analyzer
Trimester Specific Hemoglobin Reference Interval	Each participant's blood samples are run immediately after phlebotomy within 30 minutes	Hemoglobin in gram/deciLiter (g/dL), measured on DxH900 hematology analyzer
Trimester Specific Red Blood Cell Count Reference Interval	Each participant's blood samples are run immediately after phlebotomy within 30 minutes	Red blood cell count in million cells/μl (M/μl), measured on DxH900 hematology analyzer
Trimester Specific White Blood Cell Count Reference Interval	Each participant's blood samples are run immediately after phlebotomy within 30 minutes	White blood cell count in thousand cells/μl (K/μl), measured on DxH900 hematology analyzer
Trimester Specific Hematocrit Reference Interval	Each participant's blood samples are run immediately after phlebotomy within 30 minutes	percentage of hematocrit (%), measured on DxH900 Hematology Analyzer
Trimester Specific Platelet Reference Interval	Each participant's blood samples are run immediately after phlebotomy within 30 minutes	Platelet in thousand cells/microLiter (K/μl), Measured on DxH900 Hematology Analyzer