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

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

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.

Study Overview

• Status: Completed
• Conditions: Pregnancy Related
• Intervention / Treatment: Diagnostic test: complete blood count, PT, aPTT, fibrinogen tests

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

• Study Type: Observational
• Enrollment (Actual): 879

Contacts and Locations

Study Locations

• Vietnam
  • Ho Chi Minh, Vietnam, 700000
    • Hung Vuong Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

pregnant women at obstetrics clinics at Hung Vuong Hospital

Description

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 Plan

How is the study designed?

Number of groups / cohorts

3

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
First trimester; Pregnant women with gestational age ≤ 13 weeks and 6 days	Diagnostic test: complete blood count, PT, aPTT, fibrinogen tests; Pregnant women who are eligible for the study will have their blood collected to run complete blood count, PT, aPTT, fibrinogen tests
Second trimester; Pregnant women with gestational age from 14 weeks and 0 days to 27 weeks and 6 days	Diagnostic test: complete blood count, PT, aPTT, fibrinogen tests; Pregnant women who are eligible for the study will have their blood collected to run complete blood count, PT, aPTT, fibrinogen tests
Third trimester; Pregnant women with gestational age ≥ 28 weeks	Diagnostic test: complete blood count, PT, aPTT, fibrinogen tests; Pregnant women who are eligible for the study will have their blood collected to run complete blood count, PT, aPTT, fibrinogen tests

What is the study measuring?

Primary Outcome Measures

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

Collaborators and Investigators

• Sponsor: Hung Vuong Hospital
• Collaborators: MITALAB COMPANY LIMITED
• Investigators: Principal Investigator: Huan N Pham, Doctor, Hung Vuong Hospital

Publications and helpful links

General Publications

• de Haas S, Ghossein-Doha C, van Kuijk SM, van Drongelen J, Spaanderman ME. Physiological adaptation of maternal plasma volume during pregnancy: a systematic review and meta-analysis. Ultrasound Obstet Gynecol. 2017 Feb;49(2):177-187. doi: 10.1002/uog.17360.
• Gong JM, Shen Y, He YX. Reference Intervals of Routine Coagulation Assays During the Pregnancy and Puerperium Period. J Clin Lab Anal. 2016 Nov;30(6):912-917. doi: 10.1002/jcla.21956. Epub 2016 Apr 7.
• Jin Y, Lu J, Jin H, Fei C, Xie X, Zhang J. Reference intervals for biochemical, haemostatic and haematological parameters in healthy Chinese women during early and late pregnancy. Clin Chem Lab Med. 2018 May 24;56(6):973-979. doi: 10.1515/cclm-2017-0804.
• Cui C, Yang S, Zhang J, Wang G, Huang S, Li A, Zhang Y, Qiao R. Trimester-specific coagulation and anticoagulation reference intervals for healthy pregnancy. Thromb Res. 2017 Aug;156:82-86. doi: 10.1016/j.thromres.2017.05.021. Epub 2017 May 24.

Helpful Links

• Defining, Establishing, and Verifying Reference Intervals in the Clinical Laboratory, 3rd Edition

Study record dates

Study Major Dates

• Study Start (Actual): June 9, 2023
• Primary Completion (Actual): August 21, 2023
• Study Completion (Actual): August 21, 2023

Study Registration Dates

• First Submitted: June 22, 2023
• First Submitted That Met QC Criteria: June 30, 2023
• First Posted (Actual): July 3, 2023

Study Record Updates

• Last Update Posted (Actual): June 4, 2025
• Last Update Submitted That Met QC Criteria: May 15, 2025
• Last Verified: May 1, 2025

More Information

Terms related to this study

• Keywords: pregnancy; Reference intervals; complete blood count; coagulation tests
• Other Study ID Numbers: CS/HV/23/13

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: data collected will be available when study is completed
• IPD Sharing Time Frame: starting 6 months after publication
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No