3 - Biochemical
Health and Nutrition Assessment Handbook (HNAH)
3 - Biochemical
July 2026
Hemoglobin (Hgb) testing is commonly used to screen for iron-deficiency anemia. Measurements of Hgb reflect the amount of functional iron in the body. Changes in Hgb concentration occur at the late stages of iron deficiency. While Hgb is not a direct measure of iron status and does not distinguish among different types of anemia, it is a useful indicator of iron-deficiency anemia.
Equipment and materials for testing
Analyzers
Analyzers are purchased by the state agency (SA).
Analyzers are Clinical Laboratory Improvement Amendment (CLIA) waived. A current copy of the certificate of waiver for the analyzers is available on the LA Portal. The certificate should be displayed where the testing is conducted.
Microcuvettes
Microcuvettes are purchased by LAs.
Store microcuvettes at room temperature, away from any direct heat source.
Microcuvette vials must be kept tightly capped. Unopened microcuvettes are good until the expiration date printed on each vial. Do not use an expired microcuvette.
Microcuvettes should be removed from the vial with gloved hands as needed before testing.
Microcuvettes must be disposed of once expired in a biohazard sharps container.
Capillary blood sampling lancets
Lancets are purchased by LAs.
Lancets must be sterile, single-use, retractable and disposable.
According to the World Health Organization (WHO) blood draw guidelines from 2010, the recommended lancet depth is 2.0-2.2 mm for adults and 1.5 mm for children and infants.
Equipment order
LAs will order microcuvettes through McKesson.
Analyzers will be ordered through the SA. Upon receipt, send an email to WICOperations@health.mo.gov with the LA’s name and the number of analyzers received within one week of receiving the shipment.
Email the SA at WICOperations@health.mo.gov or call 1-800-392-8209 regarding broken or replacement analyzers.
Safety
Since blood is the primary carrier of the hepatitis C virus (HCV), hepatitis B virus (HBV) and human immunodeficiency virus (HIV), standard (universal) precautions are required.
- Wear protective gloves.
- Dispose of lancets and microcuvettes in a puncture-proof biohazard sharps container.
- Dispose of all blood-soaked items in biohazard-marked bags.
- Open an individually wrapped adhesive bandage (i.e., Band-Aid) at the time of the procedure to cover the puncture site. Do not stick bandages to another surface (e.g., clothing, wall, tabletop) before use.
Hematological testing training
Qualified LA staff must complete HemoCue training and have their skills validated before performing Hgb blood testing with participants.
HemoCue training can be completed by watching the recorded HemoCue Hb 301 System training and taking the HemoCue and Biochemical Assessment Quiz on the Training page in the LA Portal. Live training sessions from HemoCue can replace recorded training when available. The recorded training can be viewed as a refresher, a corrective action plan (CAP) or on an as-needed basis.
Skills validation must be completed prior to performing Hgb screenings. This skills validation can be provided by a state nutritionist, the nutrition coordinator or a manufacturer-provided trainer. The validator must complete the Capillary Sampling Skills Checklist.
- Nutrition coordinators will have their skills validated by a state nutritionist or the manufacturer before they can validate LA staff skills.
Document all training in the WIC Staff Training Record and retain certificates of completion.
Anemia screening guidelines
Only a physician or health care provider can diagnose anemia. The anemia screening conducted at a WIC clinic provides information about the participant’s hemoglobin (Hgb) status, enabling staff to identify relevant nutrition risks, guide nutrition education and make appropriate referrals.
Data must be collected within the same WIC program category as determined at certification or mid-certification (MCA), as explained below.
| WIC category | Time frames to collect blood work data | Other issues specific to the category or age |
|---|---|---|
| Pregnant women | At the earliest opportunity during the pregnancy, usually the first visit. | N/A |
| Breastfeeding and postpartum women | After termination of the pregnancy, ideally four to six weeks postpartum. Blood work must not be taken before four weeks postpartum. | If certified after six weeks postpartum, take blood work at the time of certification. For breastfeeding women six to 12 months postpartum, no additional blood work is required if a blood test was already obtained after delivery and documented. |
| Infants 0- <12 months of age | Between nine and <12 months of age. | A blood test before nine months of age may be appropriate for preterm and low-birth-weight infants not fed iron-fortified formula. |
| Children 12- <24 months of age | Between 15 and 18 months of age. One blood test is required between 12 and 24 months of age, ideally to be done six months after the infant’s initial blood work. | A blood test taken at or before 12 months cannot fulfill the requirement for both the infant and the 12 to <24 months of age child screening. |
| Children 2-5 years of age | Once every 12 months for children whose blood test results were within the normal range at their last screening. | Recheck in six months if risk factor 201 was assigned. |
If an applicant, participant or their parent or guardian refuses blood work, the participant must be placed on a monthly cycle until the data is collected. Select the Delayed Bloodwork toggle in the Bloodwork tab and document the reason or the refusal in the Management Information System (MIS).
Procedure for capillary testing
All women, infants and children must have a finger stick.
Toe and heel sticks are not allowed for infants.
- Wash your hands and wear gloves.
- Prepare the HemoCue Hb 301 system by placing the cuvette holder in the loading position. The display will show three flashing dashes and the HemoCue symbol.
- Remove a microcuvette from the vial and recap the vial immediately.
- Make sure the hand is warm and relaxed. For best results, use the middle or ring finger for sampling. Avoid using fingers with rings.
- Clean the puncture site with alcohol. Wipe off the alcohol with a clean, dry, lint-free wipe, or let it air-dry completely.
- Use a rolling motion with the thumb to lightly press the finger from the top of the upper joint to the tip. This stimulates the blood flow toward the sampling point.
- While maintaining gentle pressure on the fingertip, seat the lancet firmly against the finger and puncture the finger. For the best blood flow and the least pain, take the sample on the side of the finger at the 11 o’clock or one o’clock position, not the center. Discard the lancet in an approved container.
- Use dry gauze or other lint-free wipes to wipe away the first two or three large drops of blood. Apply gentle pressure with a rolling motion, if necessary, until another drop of blood appears. This encourages blood flow and reduces the chance of dilution from interstitial fluid. Avoid “milking the finger.”
- Ensure that the blood drop is sufficiently large, approximately the size of a split pea, before filling the microcuvette.
- Hold the microcuvette by the “wing” end and position the tip point down into the center of the blood drop. Fill the microcuvette completely in one continuous motion. Do not refill a partially filled microcuvette.
- Wipe off any excess blood from the outside of the microcuvette using a clean, lint-free wipe, taking care not to touch the open end (rounded side and tip).
- Visually inspect the microcuvette for air bubbles. If bubbles are present, discard the microcuvette.
- The filled microcuvette must be analyzed as soon as possible, within 40 seconds after it has been filled. It must be kept in a horizontal position. Place the filled microcuvette into the cuvette holder and gently nudge the flap to move the holder into the measuring position. Depending on the analyzer, the result will be displayed within three to 10 seconds. Document the result before pulling the cuvette holder out to the loading position. Remove the microcuvette and discard it in an appropriate biohazard container.
- Turn the power switch to “off” after all testing for the day.
Clean blood spills on the counter or work surface with a 10 percent bleach solution or an approved disinfectant.
Change gloves between all participants, including family members.
When lead and Hgb samples are taken from the same finger stick, see the Procedure for lead and Hgb testing using the same finger stick section below.
Low Hgb value result
A participant with low Hgb should be referred to their health care provider. Blood work must be repeated six months later if risk factor 201 is assigned.
Analyzer maintenance and repair
Maintenance
All equipment that comes into contact with blood must be handled as potentially infectious, in accordance with universal precautions and good laboratory practices. Wear gloves when cleaning the optical parts of the analyzers.
The analyzer has an internal quality control, the “self-test.” Every time the analyzer is turned on, it automatically verifies the performance of the optronic unit. If the analyzer remains switched on, this test is performed every second hour. Upon passing the “self-test,” the display will show three flashing dashes, indicating that the analyzer is ready to perform a measurement. An error code will be displayed if the “self-test” fails.
The cuvette holder and the exterior of the analyzer should be cleaned at the end of each day.
- Check that the analyzer is turned off. The display should be blank.
- Pull the cuvette holder out to its loading position. Press the small catch in the upper-right corner of the cuvette holder. While pressing the catch or small silver button with the tip of a pen or pencil, carefully rotate the cuvette holder towards the left as far as possible. Remove the holder from the analyzer. It will come off the stainless-steel pin it rotates on.
- Clean the cuvette holder and exterior with 20-70 percent alcohol or alcohol prep pads.
- Wait 15 minutes before replacing the cuvette holder and using the analyzer. Make sure the cuvette holder is dry before using.
When an error message appears on the display screen, clean the analyzer's optical part with 20-70 percent alcohol or the manufacturer's cleaner. A dirty optronic unit may cause the analyzer to display an error code.
- It is not recommended to use alcohol prep pads to clean the optics because the prep pad contains additional agents that will leave a residue on the optics.
- To clean the optronic unit, use two cotton-tipped swabs moistened with 20-70 percent alcohol or manufacturer cleaner. Insert the swabs into the opening of the cuvette holder and move them from side to side 5-10 times. If the swabs are stained, repeat the process. If the swabs remain clean, no further cleaning is required.
- Let the optronic unit dry for 15 minutes before replacing the cuvette holder.
Repair
If your agency has any questions regarding hematological testing equipment, please contact your district nutritionist and not the manufacturer.
WIC requirement for lead assessment
For children ages 1-5, ask whether a lead screening or test was conducted within the last year. Lead screening involves asking whether the child has had a blood lead test or whether screening was conducted using the Missouri Healthy Children and Youth (HCY) Lead Risk Assessment Guide to determine whether a blood lead test is needed.
A lead test, also known as a blood lead test, measures the amount of lead in a person’s blood. There are two types of lead tests:
- Capillary blood test: This screening test is often the first step and can provide fast results. This test is completed by pricking the finger to collect blood.
- Venous blood test: This test is more accurate, as it involves drawing blood from a vein in the arm. Results may take a few days to be available.
Based on recommendations issued by the Missouri Department of Health and Senior Services, provide a referral to children who have not had a lead screening or test to a testing program. Document lead referrals in the MIS as Lead Screening and Local Health Department or Medical and Dental Health Services.
Document known lead values in the Bloodwork page of the MIS. If a participant has been assigned risk factor 211, refer them to their health care provider.
LAs may ask a pregnant woman if she has had a lead screening or test.
Procedure for lead and Hgb testing using the same finger stick
When a non-WIC entity, i.e., a health department or center, fulfills its requirement for a blood test at the same time (using the same finger) as Hgb testing at the WIC appointment:
- Take Hgb first, unless otherwise instructed by the product used to collect the lead sample. If the lead sample is collected first, the integrity of the Hgb sample must be preserved by:
- Maintaining gentle pressure on the tip of the finger without “milking the finger.”
- Filling the microcuvette with the third or fourth large drop of blood.
- Filling the microcuvette properly with the point down.
- Filling the microcuvette completely. Do not refill a partially filled microcuvette.
- Participants must be advised that lead testing is not required to receive WIC benefits.
Blood lead testing is not an allowable WIC cost. WIC program funds cannot be used to provide blood lead testing or to purchase lead testing equipment. When WIC staff perform blood lead testing, the time spent conducting the test must be billed to another funding source.
Capillary Sampling Skills Checklist
A state agency nutritionist, the nutrition coordinator or a manufacturer-provided trainer must validate each employee's Hemoglobin screening skills before they perform the screening.
The Capillary Sampling Skills Checklist must be used and successfully completed with a score of 75 percent or greater.
If skills validation is completed by HemoCue, it is acceptable to use HemoCue’s Capillary Sampling Skills Checklist as proof of completion.
There are two skill sections to assess: preparation and screening.
Preparation
| Skills to assess | Steps to accomplish the skill |
|---|---|
| Assembled supplies needed. |
|
| Ensured participant was ready for Hgb screening. |
|
| Appropriately handled the microcuvettes. |
|
| Used the appropriate safety precautions. |
|
| Used the middle or ring finger for sampling. |
|
| Cleaned and dried the site or allowed the site to dry completely. |
|
| Primed the site. |
|
Screening
| Skills to assess | Steps to accomplish the skill |
|---|---|
| Maintained pressure on the fingertip when performing the finger stick. | Maintained gentle but firm pressure on the finger being used for sampling until the lancet was activated. |
| Positioned and activated the lancet correctly. | Sampled on the side of the finger at the 11 o’clock or one o’clock position, not in the center. |
| Wiped away 2-3 good-sized drops of blood. |
|
| Positioned the microcuvette properly. | Held the microcuvette by the “wing” end and positioned the tip point down into the center of the blood drop. |
| Filled the microcuvette completely in one continuous motion. | Did not refill a partially filled microcuvette. |
| Wiped the microcuvette and checked for air bubbles. |
|
| Inserted the filled microcuvette into the analyzer. |
|
| Disposed of the lancet and microcuvette in the appropriate container. | Disposed of in a biohazard container. |